This is a complete list of former United States representatives whose last names begin with the letter M.
The number of years the representative/delegate has served in Congress indicates the number of terms the representative/delegate has. Note the representative/delegate can also serve non-consecutive terms if the representative/delegate loses election and wins re-election to the House.
| Representative/Delegate | Years | State/Territory | Party | Lifespan |
|---|---|---|---|---|
| Melvin Maas | 1927–1933 1935–1945 | Minnesota | Republican | 1898–1964 |
| Tom MacArthur | 2015–2019 | New Jersey | Republican | 1960–present |
| John MacCrate | 1919–1920 | New York | Republican | 1885–1976 |
| John L. MacDonald | 1887–1889 | Minnesota | Democratic | 1838–1903 |
| Moses Macdonald | 1851–1855 | Maine | Democratic | 1815–1869 |
| Torbert Macdonald | 1955–1976 | Massachusetts | Democratic | 1917–1976 |
| William Josiah MacDonald | 1913–1915 | Michigan | Progressive | 1873–1946 |
| Clinton D. MacDougall | 1873–1877 | New York | Republican | 1839–1914 |
| Daniel Mace | 1851–1855 | Indiana | Democratic | 1811–1867 |
| 1855–1857 | Oppositionist | |||
| Clarence MacGregor | 1919–1928 | New York | Republican | 1872–1952 |
| Clark MacGregor | 1961–1971 | Minnesota | Republican | 1922–2003 |
| Hervey Machen | 1965–1969 | Maryland | Democratic | 1916–1994 |
| James Machir | 1797–1799 | Virginia | Federalist | 1764–1827 |
| Thaddeus M. Machrowicz | 1951–1961 | Michigan | Democratic | 1899–1970 |
| Ronald Machtley | 1989–1995 | Rhode Island | Republican | 1948–present |
| A. F. Maciejewski | 1939–1942 | Illinois | Democratic | 1893–1949 |
| Archibald T. MacIntyre | 1871–1873 | Georgia | Democratic | 1822–1900 |
| Lucien J. Maciora | 1941–1943 | Connecticut | Democratic | 1902–1993 |
| Connie Mack III | 1983–1989 | Florida | Republican | 1940–present |
| Connie Mack IV | 2005–2013 | Florida | Republican | 1967–present |
| Peter F. Mack Jr. | 1949–1963 | Illinois | Democratic | 1916–1986 |
| Russell V. Mack | 1947–1960 | Washington | Republican | 1891–1960 |
| Buddy MacKay | 1983–1989 | Florida | Democratic | 1933–2024 |
| James MacKay | 1965–1967 | Georgia | Democratic | 1919–2004 |
| Edmund W. M. Mackey | 1875–1876 | South Carolina | Independent Republican | 1846–1884 |
| 1882–1884 | Republican | |||
| Levi A. Mackey | 1875–1879 | Pennsylvania | Democratic | 1819–1889 |
| John C. Mackie | 1965–1967 | Michigan | Democratic | 1920–2008 |
| George MacKinnon | 1947–1949 | Minnesota | Republican | 1906–1995 |
| James H. MacLafferty | 1922–1925 | California | Republican | 1871–1937 |
| Samuel Maclay | 1795–1797 | Pennsylvania | Democratic-Republican | 1741–1811 |
| William Maclay | 1815–1819 | Pennsylvania | Democratic-Republican | 1765–1825 |
| William B. Maclay | 1843–1849 1857–1861 | New York | Democratic | 1812–1882 |
| William Plunkett Maclay | 1816–1821 | Pennsylvania | Democratic-Republican | 1774–1842 |
| Nathaniel Macon | 1791–1795 | North Carolina | Anti-Administration | 1757–1837 |
| 1795–1815 | Democratic-Republican | |||
| Robert B. Macon | 1903–1913 | Arkansas | Democratic | 1859–1925 |
| John B. Macy | 1853–1855 | Wisconsin | Democratic | 1799–1856 |
| W. Kingsland Macy | 1947–1951 | New York | Republican | 1889–1961 |
| Martin B. Madden | 1905–1928 | Illinois | Republican | 1855–1928 |
| Ray Madden | 1943–1977 | Indiana | Democratic | 1892–1987 |
| John W. Maddox | 1893–1905 | Georgia | Democratic | 1848–1922 |
| Ed Madigan | 1973–1991 | Illinois | Republican | 1936–1994 |
| Edmond H. Madison | 1907–1911 | Kansas | Republican | 1865–1911 |
| James Madison | 1789–1795 | Virginia | Anti-Administration | 1751–1836 |
| 1795–1797 | Democratic-Republican | |||
| Dan Maffei | 2009–2011 2013–2015 | New York | Democratic | 1968–present |
| James T. Maffett | 1887–1889 | Pennsylvania | Republican | 1837–1912 |
| Clare Magee | 1949–1953 | Missouri | Democratic | 1899–1969 |
| James M. Magee | 1923–1927 | Pennsylvania | Republican | 1877–1949 |
| John Magee | 1827–1831 | New York | Democratic | 1794–1868 |
| John A. Magee | 1873–1875 | Pennsylvania | Democratic | 1827–1903 |
| Walter W. Magee | 1915–1927 | New York | Republican | 1861–1927 |
| Martin Maginnis | 1873–1885 | Montana | Republican | 1841–1919 |
| Thomas F. Magner | 1889–1895 | New York | Democratic | 1860–1945 |
| Don Magnuson | 1953–1963 | Washington | Democratic | 1911–1979 |
| Warren Magnuson | 1937–1944 | Washington | Democratic | 1905–1989 |
| Henry S. Magoon | 1875–1877 | Wisconsin | Republican | 1832–1889 |
| Frederick W. Magrady | 1925–1933 | Pennsylvania | Republican | 1863–1954 |
| Patrick Magruder | 1805–1807 | Maryland | Democratic-Republican | 1768–1819 |
| Andrew Maguire | 1975–1981 | New Jersey | Democratic | 1939–present |
| James G. Maguire | 1893–1899 | California | Democratic | 1853–1920 |
| John A. Maguire | 1909–1915 | Nebraska | Democratic | 1870–1939 |
| Bryan F. Mahan | 1913–1915 | Connecticut | Democratic | 1856–1923 |
| Rowland B. Mahany | 1895–1899 | New York | Republican | 1864–1937 |
| James P. Maher | 1911–1921 | New York | Democratic | 1865–1946 |
| Gabriel H. Mahon Jr. | 1936–1939 | South Carolina | Democratic | 1889–1962 |
| George H. Mahon | 1935–1979 | Texas | Democratic | 1900–1985 |
| Thaddeus M. Mahon | 1903–1907 | Pennsylvania | Republican | 1840–1916 |
| Peter P. Mahoney | 1885–1889 | New York | Democratic | 1848–1889 |
| Tim Mahoney | 2007–2009 | Florida | Democratic | 1956–present |
| William F. Mahoney | 1901–1904 | Illinois | Democratic | 1856–1904 |
| William S. Mailliard | 1953–1974 | California | Republican | 1917–1992 |
| Verner Main | 1935–1937 | Michigan | Republican | 1885–1965 |
| Levi Maish | 1875-1879 1887-1891 | Pennsylvania | Democratic | 1837–1899 |
| Denise Majette | 2003–2005 | Georgia | Democratic | 1955–present |
| James Earl Major | 1923–1925 1927–1929 1931–1933 | Illinois | Democratic | 1887–1972 |
| Samuel C. Major | 1919–1921 1923–1929 1931 | Missouri | Democratic | 1869–1931 |
| Thomas Jefferson Majors | 1878–1879 | Nebraska | Republican | 1841–1932 |
| Francis Malbone | 1793–1795 | Rhode Island | Pro-Administration | 1759–1809 |
| 1795–1797 | Federalist | |||
| George R. Malby | 1907–1912 | New York | Republican | 1857–1912 |
| Tom Malinowski | 2019–2023 | New Jersey | Democratic | 1965–present |
| Richard W. Mallary | 1972–1975 | Vermont | Republican | 1929–2011 |
| Rollin Carolas Mallary | 1820–1825 | Vermont | Democratic-Republican | 1784–1831 |
| 1825–1831 | National Republican | |||
| Francis Mallory | 1837–1843 | Virginia | Whig | 1807–1860 |
| Meredith Mallory | 1839–1841 | New York | Democratic | 1781–1855 |
| Robert Mallory | 1859–1861 | Kentucky | Oppositionist | 1815–1885 |
| 1861–1865 | Unionist | |||
| Rufus Mallory | 1867–1869 | Oregon | Republican | 1831–1914 |
| Stephen Mallory II | 1891–1895 | Florida | Democratic | 1848–1907 |
| Carolyn Maloney | 1993–2023 | New York | Democratic | 1946–present |
| Francis T. Maloney | 1933–1935 | Connecticut | Democratic | 1894–1945 |
| Franklin J. Maloney | 1947–1949 | Pennsylvania | Republican | 1899–1958 |
| James H. Maloney | 1997–2003 | Connecticut | Democratic | 1948–present |
| Paul H. Maloney | 1931–1940 1943–1947 | Louisiana | Democratic | 1876–1967 |
| Robert S. Maloney | 1921–1923 | Massachusetts | Republican | 1881–1934 |
| Sean Patrick Maloney | 2013–2023 | New York | Democratic | 1966–present |
| James Manahan | 1913–1915 | Minnesota | Republican | 1866–1932 |
| Carter Manasco | 1941–1949 | Alabama | Democratic | 1902–1992 |
| Willie P. Mangum | 1823–1825 | North Carolina | Democratic-Republican | 1792–1861 |
| 1825–1826 | Democratic | |||
| Helen Douglas Mankin | 1946–1947 | Georgia | Democratic | 1896–1956 |
| Joe J. Manlove | 1923–1933 | Missouri | Republican | 1876–1956 |
| Abijah Mann Jr. | 1833–1837 | New York | Republican | 1793–1868 |
| David S. Mann | 1993–1995 | Ohio | Democratic | 1939–present |
| Edward C. Mann | 1919–1921 | South Carolina | Democratic | 1880–1931 |
| Horace Mann | 1848–1851 | Massachusetts | Whig | 1796–1859 |
| 1851–1853 | Free Soiler | |||
| James Mann | 1868 | Louisiana | Democratic | 1822–1868 |
| James R. Mann | 1897–1922 | Illinois | Republican | 1856–1922 |
| James Mann | 1969–1979 | South Carolina | Democratic | 1920–2010 |
| Job Mann | 1835-1837 1847-1851 | Pennsylvania | Democratic | 1795–1873 |
| Joel Keith Mann | 1831–1835 | Pennsylvania | Democratic | 1780–1857 |
| John Manning Jr. | 1870–1871 | North Carolina | Democratic | 1830–1899 |
| Kathy Manning | 2021–2025 | North Carolina | Democratic | 1956–present |
| Richard Irvine Manning I | 1834–1836 | South Carolina | Democratic | 1789–1836 |
| Van H. Manning | 1877–1883 | Mississippi | Democratic | 1839–1892 |
| Joseph J. Mansfield | 1917–1947 | Texas | Democratic | 1861–1947 |
| Mike Mansfield | 1943–1953 | Montana | Democratic | 1903–2001 |
| Mahlon Dickerson Manson | 1871–1873 | Indiana | Democratic | 1820–1895 |
| Charles H. Mansur | 1887–1893 | Missouri | Democratic | 1835–1895 |
| Thomas Manton | 1985–1999 | New York | Democratic | 1932–2006 |
| Francisco Antonio Manzanares | 1884–1885 | New Mexico | Democratic | 1843–1904 |
| Don Manzullo | 1993–2013 | Illinois | Republican | 1944–present |
| Carl E. Mapes | 1913–1939 | Michigan | Republican | 1874–1939 |
| John Hartwell Marable | 1825–1829 | Tennessee | Democratic | 1786–1844 |
| Joseph J. Maraziti | 1973–1975 | New Jersey | Republican | 1912–1991 |
| Vito Marcantonio | 1935–1937 | New York | Republican | 1902–1954 |
| 1939–1951 | American Laborite | |||
| Albert Gallatin Marchand | 1839–1843 | Pennsylvania | Democratic | 1811–1848 |
| David Marchand | 1817–1821 | Pennsylvania | Democratic-Republican | 1776–1832 |
| Kenny Marchant | 2005–2021 | Texas | Republican | 1951–present |
| Daniel Marcy | 1863–1865 | New Hampshire | Democratic | 1809–1893 |
| Samuel W. Mardis | 1831–1835 | Alabama | Democratic | 1800–1836 |
| Marjorie Margolies | 1993–1995 | Pennsylvania | Democratic | 1942–present |
| Tom Marino | 2011–2019 | Pennsylvania | Republican | 1952–present |
| Robert Marion | 1805–1810 | South Carolina | Democratic-Republican | 1766–1811 |
| Henry Markell | 1825–1829 | New York | National Republican | 1792–1831 |
| Jacob Markell | 1813–1815 | New York | Federalist | 1770–1852 |
| Betsy Markey | 2009–2011 | Colorado | Democratic | 1956–present |
| Ed Markey | 1976–2013 | Massachusetts | Democratic | 1946–present |
| Henry Markham | 1885–1887 | California | Republican | 1840–1923 |
| Philip S. Markley | 1823–1825 | Pennsylvania | Democratic-Republican | 1789–1834 |
| 1825–1827 | National Republican | |||
| Marc L. Marks | 1977–1983 | Pennsylvania | Republican | 1927–2018 |
| E. W. Marland | 1933–1935 | Oklahoma | Democratic | 1874–1941 |
| Ron Marlenee | 1977–1993 | Montana | Republican | 1935–2020 |
| Turner M. Marquett | 1867 | Nebraska | Republican | 1831–1894 |
| Alem Marr | 1829–1831 | Pennsylvania | Democratic | 1787–1843 |
| George Washington Lent Marr | 1817–1819 | Tennessee | Democratic-Republican | 1779–1856 |
| David Daniel Marriott | 1977–1985 | Utah | Republican | 1939–present |
| John H. Marsalis | 1949–1951 | Colorado | Democratic | 1904–1971 |
| Benjamin F. Marsh | 1877–1883 1893–1901 1903–1905 | Illinois | Republican | 1839–1905 |
| Charles Marsh | 1815–1817 | Vermont | Federalist | 1765-1849 |
| George Perkins Marsh | 1843–1849 | Vermont | Whig | 1801–1882 |
| John O. Marsh Jr. | 1963–1971 | Virginia | Democratic | 1926–2019 |
| Alexander Keith Marshall | 1855–1857 | Kentucky | American | 1808–1884 |
| Alfred Marshall | 1841–1843 | Maine | Democratic | c. 1797–1868 |
| Edward C. Marshall | 1851–1853 | California | Democratic | 1821–1893 |
| Fred Marshall | 1949–1963 | Minnesota | Democratic-Farmer-Labor | 1906–1985 |
| George Alexander Marshall | 1897–1899 | Ohio | Democratic | 1851–1899 |
| Humphrey Marshall | 1849–1852 | Kentucky | Whig | 1812–1872 |
| 1855–1859 | American | |||
| James W. Marshall | 1893–1895 | Virginia | Democratic | 1844–1911 |
| Jim Marshall | 2003–2011 | Georgia | Democratic | 1948–present |
| John Marshall | 1799–1800 | Virginia | Federalist | 1755–1835 |
| L. L. Marshall | 1939–1941 | Ohio | Republican | 1888–1958 |
| Leroy T. Marshall | 1933–1937 | Ohio | Republican | 1883–1950 |
| Roger Marshall | 2017–2021 | Kansas | Republican | 1960–present |
| Samuel S. Marshall | 1855–1859 1865–1875 | Illinois | Democratic | 1821–1890 |
| Thomas A. Marshall | 1831–1835 | Kentucky | National Republican | 1794–1871 |
| Thomas Francis Marshall | 1841–1843 | Kentucky | Whig | 1801–1864 |
| Thomas F. Marshall | 1901–1909 | North Dakota | Republican | 1854–1921 |
| Gilman Marston | 1859–1863 1865–1867 | New Hampshire | Republican | 1811–1890 |
| Augustus N. Martin | 1889–1895 | Indiana | Democratic | 1847–1901 |
| Barclay Martin | 1845–1847 | Tennessee | Democratic | 1802–1890 |
| Benjamin F. Martin | 1877–1881 | West Virginia | Democratic | 1828–1895 |
| Charles Martin | 1917 | Illinois | Democratic | 1856–1917 |
| Charles D. Martin | 1859–1861 | Ohio | Democratic | 1829–1911 |
| Charles Henry Martin | 1896–1899 | North Carolina | Populist | 1848–1931 |
| Charles Martin | 1931–1935 | Oregon | Democratic | 1863–1946 |
| David O'Brien Martin | 1981–1993 | New York | Republican | 1944–2012 |
| David Martin | 1961–1974 | Nebraska | Republican | 1907–1997 |
| Eben Martin | 1901–1907 1908–1915 | South Dakota | Republican | 1855–1932 |
| Edward L. Martin | 1879–1883 | Delaware | Democratic | 1837-1897 |
| Elbert S. Martin | 1859–1861 | Virginia | Independent Democratic | c. 1829-1876 |
| Frederick S. Martin | 1851–1853 | New York | Whig | 1794-1865 |
| James D. Martin | 1965–1967 | Alabama | Republican | 1918–2017 |
| James G. Martin | 1973–1985 | North Carolina | Republican | 1935–present |
| James Stewart Martin | 1873–1875 | Illinois | Republican | 1826–1907 |
| John Andrew Martin | 1909–1913 1933–1939 | Colorado | Democratic | 1868–1939 |
| John C. Martin | 1939–1941 | Illinois | Democratic | 1880–1952 |
| John Mason Martin | 1885–1887 | Alabama | Democratic | 1837–1898 |
| John Preston Martin | 1845–1847 | Kentucky | Democratic | 1811–1862 |
| Joseph John Martin | 1879–1881 | North Carolina | Republican | 1833–1900 |
| Joseph W. Martin Jr. | 1925–1967 | Massachusetts | Republican | 1884–1968 |
| Joshua L. Martin | 1835–1839 | Alabama | Democratic | 1799–1856 |
| Lewis J. Martin | 1913 | New Jersey | Democratic | 1844–1913 |
| Lynn M. Martin | 1981–1991 | Illinois | Republican | 1939–present |
| Morgan Lewis Martin | 1845–1847 | Wisconsin | Democratic | 1805–1887 |
| Patrick M. Martin | 1963–1965 | California | Republican | 1924–1968 |
| Robert N. Martin | 1825–1827 | Maryland | National Republican | 1798–1870 |
| Thomas E. Martin | 1939–1955 | Iowa | Republican | 1893–1971 |
| Whitmell P. Martin | 1915–1919 | Louisiana | Progressive | 1867–1929 |
| 1919–1929 | Democratic | |||
| William D. Martin | 1827–1831 | South Carolina | Democratic | 1789–1833 |
| William Harrison Martin | 1887–1891 | Texas | Democratic | 1822–1898 |
| Henry C. Martindale | 1823–1831 1833–1835 | New York | National Republican | 1780–1860 |
| Matthew G. Martínez | 1982–2000 | California | Democratic | 1929–2011 |
| 2000–2001 | Republican | |||
| Bill Martini | 1995–1997 | New Jersey | Republican | 1947–present |
| Dudley Marvin | 1823-1829 1847-1849 | New York | Whig | 1786–1856 |
| Francis Marvin | 1893–1895 | New York | Republican | 1828–1905 |
| James M. Marvin | 1863–1869 | New York | Republican | 1809–1901 |
| Richard P. Marvin | 1837–1841 | New York | Whig | 1803–1892 |
| Frank Mascara | 1995–2003 | Pennsylvania | Democratic | 1930–2011 |
| Harry H. Mason | 1935–1937 | Illinois | Democratic | 1873–1946 |
| James Brown Mason | 1815–1819 | Rhode Island | Federalist | 1775–1819 |
| James M. Mason | 1837–1839 | Virginia | Democratic | 1798–1871 |
| John Calvin Mason | 1849–1853 1857–1859 | Kentucky | Democratic | 1802–1865 |
| John Thomson Mason Jr. | 1841–1843 | Maryland | Democratic | 1815–1873 |
| John Y. Mason | 1831–1837 | Virginia | Democratic | 1799–1859 |
| Jonathan Mason | 1817–1820 | Massachusetts | Federalist | 1756–1831 |
| Joseph Mason | 1879–1883 | New York | Republican | 1828–1914 |
| Moses Mason Jr. | 1833–1837 | Maine | Democratic | 1789–1866 |
| Noah M. Mason | 1937–1963 | Illinois | Republican | 1882–1965 |
| Samson Mason | 1835–1843 | Ohio | Whig | 1793–1869 |
| William Mason | 1835–1837 | New York | Democratic | 1786–1860 |
| William E. Mason | 1887–1891 1917–1921 | Illinois | Republican | 1850–1921 |
| Eric Massa | 2009–2010 | New York | Democratic | 1959–present |
| Zachary D. Massey | 1910–1911 | Tennessee | Republican | 1864–1923 |
| Sam C. Massingale | 1935–1941 | Oklahoma | Democratic | 1870–1941 |
| Josiah Masters | 1805–1809 | New York | Democratic–Republican | 1763–1822 |
| Jim Matheson | 2001–2015 | Utah | Democratic | 1960–present |
| Frank A. Mathews Jr. | 1945–1949 | New Jersey | Republican | 1890–1964 |
| George A. Mathews | 1889 | Dakota | Republican | 1852–1941 |
| George Mathews | 1789–1791 | Georgia | Anti-Administration | 1739–1812 |
| James Mathews | 1841–1845 | Ohio | Democratic | 1805–1887 |
| Vincent Mathews | 1809–1811 | New York | Federalist | 1766–1846 |
| Bob Mathias | 1967–1975 | California | Republican | 1930–2006 |
| Charles Mathias | 1961–1969 | Maryland | Republican | 1922–2010 |
| Joshua Mathiot | 1841–1843 | Ohio | Whig | 1800–1849 |
| Dawson Mathis | 1971–1981 | Georgia | Democratic | 1940–2017 |
| James Matlack | 1821–1825 | New Jersey | Democratic-Republican | 1775–1840 |
| Aaron Matson | 1821–1825 | New Hampshire | Democratic-Republican | 1770–1855 |
| Courtland C. Matson | 1881–1889 | Indiana | Democratic | 1841–1915 |
| Bob Matsui | 1979–2005 | California | Democratic | 1941–2005 |
| Spark Matsunaga | 1963–1977 | Hawaii | Democratic | 1916–1990 |
| Orsamus B. Matteson | 1853–1857 | New York | Whig | 1805–1889 |
| Charles Matthews | 1911–1913 | Pennsylvania | Republican | 1856–1932 |
| D. R. Matthews | 1953–1967 | Florida | Democratic | 1907–1997 |
| Nelson E. Matthews | 1915–1917 | Ohio | Republican | 1852–1917 |
| William Matthews | 1797–1799 | Maryland | Federalist | 1755–1808 |
| John Mattocks | 1821–1823 | Vermont | Democratic-Republican | 1777–1847 |
| 1825–1827 | National Republican | |||
| 1841–1843 | Whig | |||
| Ebenezer Mattoon | 1801–1803 | Massachusetts | Federalist | 1755–1843 |
| Jim Mattox | 1977–1983 | Texas | Democratic | 1943–2008 |
| James Maurice | 1853–1855 | New York | Democratic | 1814–1884 |
| Abram Poindexter Maury | 1835–1837 | Tennessee | National Republican | 1801–1848 |
| 1837–1839 | Whig | |||
| Maury Maverick | 1935–1939 | Texas | Democratic | 1895–1954 |
| Nicholas Mavroules | 1979–1993 | Massachusetts | Democratic | 1929–2003 |
| Augustus Maxwell | 1853–1857 | Florida | Democratic | 1820–1903 |
| George C. Maxwell | 1811–1813 | New Jersey | Democratic-Republican | 1771–1816 |
| John Patterson Bryan Maxwell | 1837–1839 1841–1843 | New Jersey | Whig | 1804–1845 |
| Lewis Maxwell | 1827–1833 | Virginia | National Republican | 1790–1862 |
| Samuel Maxwell | 1897–1899 | Nebraska | Populist | 1825–1901 |
| Thomas Maxwell | 1829–1831 | New York | Democratic | 1792–1864 |
| Andrew J. May | 1931–1947 | Kentucky | Democratic | 1875–1959 |
| Catherine Dean May | 1959–1971 | Washington | Republican | 1914–2004 |
| Edwin H. May Jr. | 1957–1959 | Connecticut | Republican | 1924–2002 |
| Henry May | 1853–1855 | Maryland | Democratic | 1816–1866 |
| 1861–1863 | Unionist | |||
| Mitchell May | 1898-1901 | New York | Democratic | 1870–1961 |
| William L. May | 1834–1839 | Illinois | Democratic | c. 1793–1849 |
| Samuel Mayall | 1853–1855 | Maine | Democratic | 1816–1892 |
| William C. Maybury | 1883–1887 | Michigan | Democratic | 1848–1909 |
| Stephen L. Mayham | 1869–1871 1877–1879 | New York | Democratic | 1826–1908 |
| Harry L. Maynard | 1901–1911 | Virginia | Democratic | 1861–1922 |
| Horace Maynard | 1857–1859 | Tennessee | American | 1814–1882 |
| 1859–1861 | Oppositionist | |||
| 1861–1863 | Unionist | |||
| 1866–1867 | Unconditional Unionist | |||
| 1867–1875 | Republican | |||
| John Maynard | 1827–1829 1838–1843 | New York | National Republican | 1786–1850 |
| Wiley Mayne | 1967–1975 | Iowa | Republican | 1917–2007 |
| Robert Murphy Mayo | 1883–1884 | Virginia | Readjuster | 1836–1896 |
| Stephanie Murphy | 2017–2023 | Florida | Democratic | 1978–present |
| William Mayrant | 1815–1816 | South Carolina | Democratic-Republican | 1765–1832 |
| Dannite H. Mays | 1909–1913 | Florida | Democratic | 1852-1930 |
| James Henry Mays | 1915–1921 | Utah | Democratic | 1868-1926 |
| Romano Mazzoli | 1971–1995 | Kentucky | Democratic | 1932–2022 |
| Ben McAdams | 2019–2021 | Utah | Democratic | 1974–present |
| William McAdoo | 1883–1891 | New Jersey | Democratic | 1853–1930 |
| William McAleer | 1891–1895 1897–1901 | Pennsylvania | Democratic | 1838–1912 |
| Archibald McAllister | 1863-1865 | Pennsylvania | Democratic | 1813–1883 |
| Vance McAllister | 2013–2015 | Louisiana | Republican | 1974–present |
| James McAndrews | 1901–1905 1913–1921 1935–1941 | Illinois | Democratic | 1862–1942 |
| Joseph A. McArdle | 1939-1942 | Pennsylvania | Democratic | 1903–1967 |
| Clifton N. McArthur | 1915–1923 | Oregon | Republican | 1879–1923 |
| Duncan McArthur | 1823–1825 | Ohio | National Republican | 1772–1839 |
| John R. McBride | 1863–1865 | Oregon | Republican | 1832–1904 |
| Archibald McBryde | 1809–1813 | North Carolina | Federalist | 1766–1836 |
| John McCain | 1983–1987 | Arizona | Republican | 1936–2018 |
| John E. McCall | 1895–1897 | Tennessee | Republican | 1859–1920 |
| Samuel W. McCall | 1893–1913 | Massachusetts | Republican | 1851–1923 |
| Al McCandless | 1983–1995 | California | Republican | 1927–2017 |
| Lincoln L. McCandless | 1933–1935 | Hawaii | Democratic | 1859–1940 |
| Carolyn McCarthy | 1997–2015 | New York | Democratic | 1944–2025 |
| Dennis McCarthy | 1867–1871 | New York | Republican | 1814–1886 |
| Eugene McCarthy | 1949–1959 | Minnesota | Democratic-Farmer-Labor | 1916–2005 |
| John H. McCarthy | 1889–1891 | New York | Democratic | 1850–1908 |
| John McCarthy | 1903–1907 | Nebraska | Republican | 1857–1943 |
| Karen McCarthy | 1995–2005 | Missouri | Democratic | 1947–2010 |
| Kevin McCarthy | 2007–2023 | California | Republican | 1965–present |
| Richard D. McCarthy | 1965–1971 | New York | Democratic | 1927–1995 |
| Andrew Z. McCarty | 1855–1857 | New York | Whig | 1808–1879 |
| Johnathan McCarty | 1831–1835 | Indiana | Democratic | 1795–1852 |
| 1835–1837 | National Republican | |||
| Richard McCarty | 1821–1823 | New York | Democratic-Republican | 1780–1844 |
| William M. McCarty | 1840–1841 | Virginia | Whig | c. 1789–1863 |
| William C. McCauslen | 1843–1845 | Ohio | Democratic | 1796–1863 |
| Charles W. McClammy | 1887–1891 | North Carolina | Democratic | 1839–1896 |
| Moses McClean | 1845–1847 | Pennsylvania | Democratic | 1804–1870 |
| James McCleary | 1893–1907 | Minnesota | Republican | 1853–1924 |
| James McCleery | 1871 | Louisiana | Republican | 1837–1871 |
| Abraham McClellan | 1837–1843 | Tennessee | Democratic | 1789–1866 |
| Charles A. O. McClellan | 1889–1893 | Indiana | Democratic | 1835–1898 |
| George McClellan | 1913–1915 | New York | Democratic | 1856–1927 |
| George B. McClellan Jr. | 1895–1903 | New York | Democratic | 1865–1940 |
| John L. McClellan | 1935–1939 | Arkansas | Democratic | 1896–1977 |
| Robert McClellan | 1837–1839 1841–1843 | New York | Democratic | 1806–1860 |
| Robert McClelland | 1843–1849 | Michigan | Democratic | 1807–1880 |
| William McClelland | 1871–1873 | Pennsylvania | Democratic | 1842–1892 |
| Blair McClenachan | 1797–1799 | Pennsylvania | Democratic-Republican | 17??–1812 |
| John A. McClernand | 1843–1851 | Illinois | Democratic | 1812–1900 |
| James V. McClintic | 1915–1935 | Oklahoma | Democratic | 1878–1948 |
| Charles B. McClintock | 1929–1933 | Ohio | Republican | 1886–1965 |
| Robert McClory | 1963–1983 | Illinois | Republican | 1908–1988 |
| Augustus McCloskey | 1929–1930 | Texas | Democratic | 1878–1950 |
| Frank McCloskey | 1983–1995 | Indiana | Democratic | 1939–2003 |
| Pete McCloskey | 1967–1983 | California | Republican | 1927–2024 |
| Addison S. McClure | 1881–1883 1895–1897 | Ohio | Republican | 1839–1903 |
| Charles McClure | 1837-1839 1840-1841 | Pennsylvania | Democratic | 1804–1846 |
| James A. McClure | 1967–1973 | Idaho | Republican | 1924–2011 |
| Joseph W. McClurg | 1863–1865 | Missouri | Unconditional Unionist | 1818–1900 |
| 1865–1868 | Republican | |||
| Moses A. McCoid | 1879–1885 | Iowa | Republican | 1840–1904 |
| John Y. McCollister | 1971–1977 | Nebraska | Republican | 1921–2013 |
| Bill McCollum | 1981–2001 | Florida | Republican | 1944–present |
| Louis E. McComas | 1883–1891 | Maryland | Republican | 1846–1907 |
| William McComas | 1833–1835 | Virginia | Democratic | 1795–1865 |
| 1835–1837 | National Republican | |||
| Felix G. McConnell | 1843–1846 | Alabama | Democratic | 1809–1846 |
| Samuel K. McConnell Jr. | 1944–1957 | Pennsylvania | Republican | 1901–1985 |
| Anson G. McCook | 1877–1883 | New York | Republican | 1835–1917 |
| Andrew McCord | 1803–1805 | New York | Democratic–Republican | c. 1754–1808 |
| Jim Nance McCord | 1943–1945 | Tennessee | Democratic | 1879–1968 |
| Myron H. McCord | 1889–1891 | Wisconsin | Republican | 1840–1908 |
| Joseph W. McCorkle | 1851–1853 | California | Democratic | 1819–1884 |
| Paul G. McCorkle | 1917 | South Carolina | Democratic | 1863–1934 |
| John W. McCormack | 1928–1971 | Massachusetts | Democratic | 1891–1980 |
| Mike McCormack | 1971–1981 | Washington | Democratic | 1921–2020 |
| Henry C. McCormick | 1887–1891 | Pennsylvania | Republican | 1844–1902 |
| James R. McCormick | 1867–1873 | Missouri | Democratic | 1824–1897 |
| John W. McCormick | 1883–1885 | Ohio | Republican | 1831–1917 |
| Medill McCormick | 1917–1919 | Illinois | Republican | 1877–1925 |
| Nelson B. McCormick | 1897–1899 | Kansas | Populist | 1847–1914 |
| Richard C. McCormick | 1869–1875 1895–1897 | Arizona New York | Republican | 1832–1901 |
| Ruth Hanna McCormick | 1929–1931 | Illinois | Republican | 1880–1944 |
| Washington J. McCormick | 1921–1923 | Montana | Republican | 1884–1949 |
| Thaddeus McCotter | 2003–2012 | Michigan | Republican | 1965–present |
| Edward Oscar McCowen | 1943–1949 | Ohio | Republican | 1877–1953 |
| Robert McCoy | 1831–1833 | Pennsylvania | Democratic | ????–1849 |
| Walter I. McCoy | 1911–1914 | New Jersey | Democratic | 1859–1933 |
| William McCoy | 1811–1825 | Virginia | Democratic-Republican | 1???–1864 |
| 1825–1833 | Democratic | |||
| Robert M. McCracken | 1915–1917 | Idaho | Republican | 1874–1934 |
| George W. McCrary | 1869–1877 | Iowa | Republican | 1835–1890 |
| John D. McCrate | 1845–1847 | Maine | Democratic | 1802–1879 |
| George D. McCreary | 1903–1913 | Pennsylvania | Republican | 1846–1915 |
| James B. McCreary | 1885–1897 | Kentucky | Democratic | 1838–1918 |
| John McCreary | 1819–1821 | South Carolina | Democratic-Republican | c. 1761-1833 |
| William Wallace McCredie | 1909–1911 | Washington | Republican | 1862–1935 |
| William McCreery | 1803–1809 | Maryland | Democratic-Republican | 1750–1814 |
| William McCreery | 1829–1831 | Pennsylvania | Democratic | 1786–1841 |
| Jim McCrery | 1988–2009 | Louisiana | Republican | 1949–present |
| George McCulloch | 1839–1841 | Pennsylvania | Democratic | 1792–1861 |
| John McCulloch | 1853–1855 | Pennsylvania | Whig | 1806–1879 |
| Philip D. McCulloch Jr. | 1893–1903 | Arkansas | Democratic | 1851–1928 |
| Roscoe C. McCulloch | 1915–1921 | Ohio | Republican | 1880–1958 |
| William Moore McCulloch | 1947–1973 | Ohio | Republican | 1901–1980 |
| Welty McCullogh | 1887–1889 | Pennsylvania | Republican | 1847–1889 |
| Hiram McCullough | 1865–1869 | Maryland | Democratic | 1813–1885 |
| Thomas G. McCullough | 1820–1821 | Pennsylvania | Federalist | 1785–1848 |
| Dave McCurdy | 1981–1995 | Oklahoma | Democratic | 1950–present |
| Joseph M. McDade | 1963–1999 | Pennsylvania | Republican | 1931–2017 |
| William McDaniel | 1846–1847 | Missouri | Democratic | 1801–1866 |
| John James McDannold | 1893–1895 | Illinois | Democratic | 1851–1904 |
| James C. McDearmon | 1893–1897 | Tennessee | Democratic | 1844–1902 |
| Allan L. McDermott | 1900–1907 | New Jersey | Democratic | 1854–1908 |
| James T. McDermott | 1907–1917 | Illinois | Democratic | 1872–1938 |
| Jim McDermott | 1989–2017 | Washington | Democratic | 1936–present |
| Alexander S. McDill | 1873–1875 | Wisconsin | Republican | 1822–1875 |
| James W. McDill | 1873–1877 | Iowa | Republican | 1834–1894 |
| Edward F. McDonald | 1891–1892 | New Jersey | Democratic | 1844–1892 |
| Jack H. McDonald | 1967–1973 | Michigan | Republican | 1932–2022 |
| John McDonald | 1897–1899 | Maryland | Republican | 1837–1917 |
| Joseph E. McDonald | 1849–1851 | Indiana | Democratic | 1819–1891 |
| Larry McDonald | 1975–1983 | Georgia | Democratic | 1935–1983 |
| Gordon L. McDonough | 1945–1963 | California | Republican | 1895–1968 |
| James A. McDougall | 1853–1855 | California | Democratic | 1817–1867 |
| Alexander McDowell | 1893–1895 | Pennsylvania | Republican | 1845–1913 |
| Harris McDowell | 1955–1957 1959–1967 | Delaware | Democratic | 1906–1988 |
| James McDowell | 1846–1851 | Virginia | Democratic | 1795–1851 |
| James F. McDowell | 1863–1865 | Indiana | Democratic | 1825–1887 |
| John McDowell | 1939–1941 1947–1949 | Pennsylvania | Republican | 1902–1957 |
| John A. McDowell | 1897–1901 | Ohio | Democratic | 1853–1927 |
| Joseph "Pleasant Gardens" McDowell | 1793–1795 | North Carolina | Anti-Administration | 1758–1799 |
| Joseph McDowell Jr. | 1797–1799 | North Carolina | Democratic-Republican | 1756–1801 |
| Joseph J. McDowell | 1843–1847 | Ohio | Democratic | 1800–1877 |
| George McDuffie | 1821–1825 | South Carolina | Democratic-Republican | 1790–1851 |
| 1825–1831 | Democratic | |||
| 1831–1834 | Nullifier | |||
| J. V. McDuffie | 1890–1891 | Alabama | Republican | 1841–1896 |
| John McDuffie | 1919–1935 | Alabama | Democratic | 1883–1950 |
| Donald McEachin | 2017–2022 | Virginia | Democratic | 1961–2022 |
| Michael J. McEttrick | 1893–1895 | Massachusetts | Independent Democrat | 1848–1921 |
| Thomas McEwan Jr. | 1895–1899 | New Jersey | Republican | 1854–1926 |
| Bob McEwen | 1981–1993 | Ohio | Republican | 1950–present |
| Robert C. McEwen | 1965–1981 | New York | Republican | 1920–1997 |
| Louis T. McFadden | 1915–1935 | Pennsylvania | Republican | 1876–1936 |
| Obadiah B. McFadden | 1873–1875 | Washington | Democratic | 1815–1875 |
| John J. McFall | 1957–1978 | California | Democratic | 1918–2006 |
| Duncan McFarlan | 1805–1807 | North Carolina | Democratic-Republican | ????–1816 |
| William McFarland | 1875–1877 | Tennessee | Democratic | 1821–1900 |
| William D. McFarlane | 1933–1939 | Texas | Democratic | 1894–1980 |
| Lawrence E. McGann | 1891–1895 | Illinois | Democratic | 1852–1928 |
| Robert N. McGarvey | 1947–1949 | Pennsylvania | Republican | 1888–1952 |
| Edward W. McGaughey | 1845–1847 1849–1851 | Indiana | Whig | 1817–1852 |
| Charles McGavin | 1905–1909 | Illinois | Republican | 1874–1940 |
| Dan R. McGehee | 1935–1947 | Mississippi | Democratic | 1883–1962 |
| Daniel J. McGillicuddy | 1911–1917 | Maine | Democratic | 1859–1936 |
| Donald McGinley | 1959–1961 | Nebraska | Democratic | 1920–2005 |
| Cornelius Augustine McGlennon | 1919–1921 | New Jersey | Democratic | 1878–1931 |
| Herbert J. McGlinchey | 1945–1947 | Pennsylvania | Democratic | 1904–1992 |
| George McGovern | 1957–1961 | South Dakota | Democratic | 1922–2012 |
| Jonas H. McGowan | 1877–1881 | Michigan | Republican | 1837–1909 |
| James P. McGranery | 1937–1943 | Pennsylvania | Democratic | 1895–1962 |
| Christopher C. McGrath | 1949-1953 | New York | Democratic | 1902–1986 |
| John J. McGrath | 1933–1939 | California | Democratic | 1872–1951 |
| Raymond J. McGrath | 1981–1993 | New York | Republican | 1942–present |
| Thomas C. McGrath Jr. | 1965–1967 | New Jersey | Democratic | 1927–1994 |
| J. Harry McGregor | 1940–1958 | Ohio | Republican | 1896–1958 |
| James McGrew | 1869–1873 | West Virginia | Republican | 1813–1910 |
| John S. McGroarty | 1935–1939 | California | Democratic | 1862–1944 |
| Harold C. McGugin | 1931–1935 | Kansas | Republican | 1893–1946 |
| Bird S. McGuire | 1903–1907 1907–1915 | Oklahoma | Republican | 1865–1930 |
| John A. McGuire | 1949–1953 | Connecticut | Democratic | 1906–1976 |
| Paul McHale | 1993–1999 | Pennsylvania | Democratic | 1950–present |
| Robert L. McHatton | 1826–1829 | Kentucky | Democratic | 1788–1835 |
| Henry D. McHenry | 1871–1873 | Kentucky | Democratic | 1826–1890 |
| John Geiser McHenry | 1907–1912 | Pennsylvania | Democratic | 1868–1912 |
| John H. McHenry | 1845–1847 | Kentucky | Whig | 1797–1871 |
| Patrick McHenry | 2005–2025 | North Carolina | Republican | 1975–present |
| John M. McHugh | 1993–2009 | New York | Republican | 1948–present |
| Matthew F. McHugh | 1975–1993 | New York | Democratic | 1938–present |
| Abraham Robinson McIlvaine | 1843–1849 | Pennsylvania | Whig | 1804–1863 |
| Walter D. McIndoe | 1863–1867 | Wisconsin | Republican | 1819–1872 |
| Scott McInnis | 1993–2005 | Colorado | Republican | 1953–present |
| Clifford McIntire | 1951–1965 | Maine | Republican | 1908–1974 |
| Rufus McIntire | 1827–1835 | Maine | Democratic | 1784–1866 |
| William W. McIntire | 1897–1899 | Maryland | Republican | 1850–1912 |
| David McIntosh | 1995–2001 | Indiana | Republican | 1958–present |
| Robert J. McIntosh | 1957–1959 | Michigan | Republican | 1922–2008 |
| John J. McIntyre | 1941–1943 | Wyoming | Democratic | 1904–1974 |
| Mike McIntyre | 1997–2015 | North Carolina | Democratic | 1956–present |
| Ebenezer McJunkin | 1871–1875 | Pennsylvania | Republican | 1819–1907 |
| William McMahon McKaig | 1891–1895 | Maryland | Democratic | 1845-1907 |
| James I McKay | 1831–1849 | North Carolina | Democratic | 1793–1853 |
| K. Gunn McKay | 1971–1981 | Utah | Democratic | 1925–2000 |
| James B. McKean | 1859–1863 | New York | Republican | 1821–1879 |
| Samuel McKean | 1823–1825 | Pennsylvania | Democratic-Republican | 1787–1841 |
| 1825–1829 | Democratic | |||
| George C. McKee | 1869–1875 | Mississippi | Republican | 1837–1890 |
| John McKee | 1823–1825 | Alabama | Democratic-Republican | 1771–1832 |
| 1825–1829 | Democratic | |||
| Samuel McKee | 1809–1817 | Kentucky | Democratic-Republican | 1774–1826 |
| Samuel McKee | 1865–1867 | Kentucky | Unconditional Unionist | 1833–1898 |
| 1868–1869 | Republican | |||
| William A. McKeighan | 1891–1895 | Nebraska | Populist | 1842–1895 |
| Kenneth McKellar | 1911–1917 | Tennessee | Democratic | 1869–1957 |
| Joseph McKenna | 1885–1892 | California | Republican | 1843–1926 |
| Thomas McKean Thompson McKennan | 1831–1839 | Pennsylvania | Anti-Masonic | 1794–1852 |
| 1842–1843 | Whig | |||
| William R. McKenney | 1895–1896 | Virginia | Democratic | 1851–1916 |
| Jacob Kerlin McKenty | 1860–1861 | Pennsylvania | Democratic | 1827–1866 |
| Charles E. McKenzie | 1943–1947 | Louisiana | Democratic | 1896–1956 |
| James A. McKenzie | 1877–1883 | Kentucky | Democratic | 1840–1904 |
| John C. McKenzie | 1911–1925 | Illinois | Republican | 1860–1941 |
| Lewis McKenzie | 1863 | Virginia | Unionist | 1810–1895 |
| 1870–1871 | Conservative | |||
| Buck McKeon | 1993–2015 | California | Republican | 1938–present |
| John McKeon | 1835–1837 1841–1843 | New York | Democratic | 1808–1883 |
| Raymond S. McKeough | 1935–1943 | Illinois | Democratic | 1888–1979 |
| Tom D. McKeown | 1917–1921 1923–1935 | Oklahoma | Democratic | 1878–1951 |
| John R. McKernan Jr. | 1983–1987 | Maine | Republican | 1948–present |
| Mike McKevitt | 1971–1973 | Colorado | Republican | 1928–2000 |
| Joseph C. McKibbin | 1857–1859 | California | Democratic | 1824–1896 |
| Alexander McKim | 1809–1815 | Maryland | Democratic-Republican | 1748–1832 |
| Isaac McKim | 1823–1825 | Maryland | Democratic-Republican | 1775–1838 |
| 1833–1838 | Democratic | |||
| Richard F. McKiniry | 1919–1921 | New York | Democratic | 1878–1950 |
| Duncan E. McKinlay | 1905–1911 | California | Republican | 1862–1914 |
| David McKinley | 2011–2023 | West Virginia | Republican | 1947–present |
| John McKinley | 1833–1835 | Alabama | Democratic | 1780–1852 |
| William McKinley | 1810–1811 | Virginia | Democratic-Republican | N/A |
| William McKinley | 1877–1884 1885–1891 | Ohio | Republican | 1843–1901 |
| William B. McKinley | 1905–1913 1915–1921 | Illinois | Republican | 1856–1926 |
| Cynthia McKinney | 1993–2003 2005–2007 | Georgia | Democratic | 1955–present |
| James McKinney | 1905–1913 | Illinois | Republican | 1852–1934 |
| John F. McKinney | 1863–1865 1871–1873 | Ohio | Democratic | 1827–1903 |
| Luther F. McKinney | 1887–1889 1891–1893 | New Hampshire | Democratic | 1841–1922 |
| Stewart McKinney | 1971–1987 | Connecticut | Republican | 1931–1987 |
| Clinton D. McKinnon | 1949–1953 | California | Democratic | 1906–2001 |
| Thomas McKissock | 1849–1851 | New York | Whig | 1790–1866 |
| Martin B. McKneally | 1969–1971 | New York | Republican | 1914–1992 |
| Robert McKnight | 1859–1863 | Pennsylvania | Republican | 1820–1885 |
| James McLachlan | 1895–1897 1901–1911 | California | Republican | 1852–1940 |
| Frank A. McLain | 1898–1909 | Mississippi | Democratic | 1852–1920 |
| James X. McLanahan | 1849–1853 | Pennsylvania | Democratic | 1809–1861 |
| Louis McLane | 1817–1825 | Delaware | Federalist | 1786–1857 |
| 1825–1827 | Democratic | |||
| Patrick McLane | 1919–1921 | Pennsylvania | Democratic | 1875–1946 |
| Robert Milligan McLane | 1847–1851 1879–1883 | Maryland | Democratic | 1815–1898 |
| Charles F. McLaughlin | 1935–1943 | Nebraska | Democratic | 1887–1976 |
| James C. McLaughlin | 1907–1932 | Michigan | Republican | 1858–1932 |
| Joseph McLaughlin | 1917–1919 1921–1923 | Pennsylvania | Republican | 1867–1926 |
| Melvin O. McLaughlin | 1919–1927 | Nebraska | Republican | 1876–1928 |
| John L. McLaurin | 1892–1897 | South Carolina | Democratic | 1860–1934 |
| Alney McLean | 1815–1817 1819–1821 | Kentucky | Democratic-Republican | 1779–1841 |
| Donald H. McLean | 1933–1945 | New Jersey | Republican | 1884–1975 |
| Finis McLean | 1849–1851 | Kentucky | Whig | 1806–1881 |
| James Henry McLean | 1882–1883 | Missouri | Republican | 1829–1886 |
| John McLean | 1813–1816 | Ohio | Democratic-Republican | 1785–1861 |
| John McLean | 1818–1819 | Illinois | None | 1791–1830 |
| Samuel McLean | 1865–1867 | Montana | None | 1826–1877 |
| William McLean | 1823–1829 | Ohio | National Republican | 1794–1839 |
| William P. McLean | 1873–1875 | Texas | Democratic | 1836–1925 |
| A. Jeff McLemore | 1915–1919 | Texas | Democratic | 1857–1929 |
| Jeremiah McLene | 1833–1837 | Ohio | Democratic | 1767–1837 |
| Clarence J. McLeod | 1920–1921 1923–1937 1939–1941 | Michigan | Republican | 1895–1959 |
| Robert T. McLoskey | 1963–1965 | Illinois | Republican | 1907–1990 |
| Gregory McMahon | 1947-1949 | New York | Republican | 1915–1989 |
| John A. McMahon | 1875–1881 | Ohio | Democratic | 1833–1923 |
| Michael McMahon | 2009–2011 | New York | Democratic | 1957–present |
| William McManus | 1825–1827 | New York | National Republican | 1780–1835 |
| Alex McMillan | 1985–1995 | North Carolina | Republican | 1932–2024 |
| Alexander McMillan | 1817 | North Carolina | Federalist | ????-1817 |
| Clara G. McMillan | 1939–1941 | South Carolina | Democratic | 1894–1976 |
| John L. McMillan | 1939–1973 | South Carolina | Democratic | 1898–1979 |
| Samuel McMillan | 1907-1909 | New York | Republican | 1850–1924 |
| Thomas S. McMillan | 1925–1939 | South Carolina | Democratic | 1888–1939 |
| William McMillan | 1800–1801 | Northwest | None | 1764–1804 |
| Rolla C. McMillen | 1944–1951 | Illinois | Republican | 1880–1961 |
| Tom McMillen | 1987–1993 | Maryland | Democratic | 1952–present |
| Benton McMillin | 1879–1899 | Tennessee | Democratic | 1845–1933 |
| Henry McMorran | 1903–1913 | Michigan | Republican | 1844–1929 |
| Cathy McMorris Rodgers | 2005–2025 | Washington | Republican | 1969–present |
| Chester B. McMullen | 1951–1953 | Florida | Democratic | 1902–1953 |
| Fayette McMullen | 1849–1857 | Virginia | Democratic | 1805–1880 |
| Howard J. McMurray | 1943–1945 | Wisconsin | Democratic | 1901–1961 |
| William F. McNagny | 1893–1895 | Indiana | Democratic | 1850–1923 |
| John McNair | 1851–1855 | Pennsylvania | Democratic | 1800–1861 |
| William S. McNary | 1903–1907 | Massachusetts | Democratic | 1863–1930 |
| Thompson W. McNeely | 1869–1873 | Illinois | Democratic | 1835–1921 |
| Archibald McNeill | 1821–1823 | North Carolina | Federalist | ????–1849 |
| 1825–1827 | Democratic | |||
| Jerry McNerney | 2007–2023 | California | Democratic | 1951–present |
| John McNulta | 1873–1875 | Illinois | Republican | 1837–1900 |
| Frank Joseph McNulty | 1923–1925 | New Jersey | Democratic | 1872–1926 |
| James F. McNulty Jr. | 1983–1985 | Arizona | Democratic | 1925–2009 |
| Michael McNulty | 1989–2009 | New York | Democratic | 1947–present |
| Edward McPherson | 1859–1863 | Pennsylvania | Republican | 1830–1895 |
| Isaac V. McPherson | 1919–1923 | Missouri | Republican | 1868–1931 |
| Smith McPherson | 1899–1900 | Iowa | Republican | 1848–1915 |
| John McQueen | 1849–1860 | South Carolina | Democratic | 1804–1867 |
| John J. McRae | 1858–1861 | Mississippi | Democratic | 1815–1868 |
| Thomas C. McRae | 1885–1903 | Arkansas | Democratic | 1851–1929 |
| Samuel Davis McReynolds | 1923–1939 | Tennessee | Democratic | 1872–1939 |
| Donald C. McRuer | 1865–1867 | California | Republican | 1826–1898 |
| Martha McSally | 2015–2019 | Arizona | Republican | 1966–present |
| John A. McShane | 1887–1889 | Nebraska | Democratic | 1850–1923 |
| James McSherry | 1821–1823 | Pennsylvania | Federalist | 1776–1849 |
| Clem McSpadden | 1973–1975 | Oklahoma | Democratic | 1925–2008 |
| John J. McSwain | 1921–1936 | South Carolina | Democratic | 1875–1936 |
| Harold B. McSween | 1959–1963 | Louisiana | Democratic | 1926–2002 |
| John McSweeney | 1923–1929 1937–1939 1949–1951 | Ohio | Democratic | 1890–1969 |
| Charles McVean | 1833–1835 | New York | Democratic | 1802–1848 |
| Walter Lewis McVey Jr. | 1961–1963 | Kansas | Republican | 1922–2014 |
| William E. McVey | 1951–1958 | Illinois | Republican | 1885–1958 |
| Roy H. McVicker | 1965–1967 | Colorado | Democratic | 1924–1973 |
| John D. McWilliams | 1943–1945 | Connecticut | Republican | 1891–1975 |
| William McWillie | 1849–1851 | Mississippi | Democratic | 1795–1869 |
| James Meacham | 1849–1855 | Vermont | Whig | 1810–1856 |
| 1855–1856 | Oppositionist | |||
| Cowles Mead | 1805 | Georgia | Democratic-Republican | 1776–1844 |
| James M. Mead | 1919-1938 | New York | Democratic | 1885–1964 |
| Edwin R. Meade | 1875–1877 | New York | Democratic | 1836–1889 |
| Hugh Meade | 1947–1949 | Maryland | Democratic | 1907–1949 |
| Richard Kidder Meade | 1847–1853 | Virginia | Democratic | 1803–1862 |
| Wendell H. Meade | 1947–1949 | Kentucky | Republican | 1912–1986 |
| George Meader | 1951–1965 | Michigan | Republican | 1907–1994 |
| Mark Meadows | 2013–2020 | North Carolina | Republican | 1959–present |
| Alexander Mebane | 1793–1795 | North Carolina | Anti-Administration | 1744–1795 |
| William Medill | 1839–1843 | Ohio | Democratic | 1802–1865 |
| Ezra Meech | 1819–1821 | Vermont | Democratic-Republican | 1773–1856 |
| 1825–1827 | Democratic | |||
| Lloyd Meeds | 1965–1979 | Washington | Democratic | 1927–2005 |
| Marty Meehan | 1993–2007 | Massachusetts | Democratic | 1956–present |
| Pat Meehan | 2011–2018 | Pennsylvania | Republican | 1955–present |
| Carrie P. Meek | 1993–2003 | Florida | Democratic | 1926–2021 |
| Kendrick Meek | 2003–2011 | Florida | Democratic | 1966–present |
| Jacob Edwin Meeker | 1915–1918 | Missouri | Republican | 1878–1918 |
| David Meekison | 1897–1901 | Ohio | Democratic | 1849–1915 |
| James A. Meeks | 1933–1939 | Illinois | Democratic | 1864–1946 |
| Henry Meigs | 1819–1821 | New York | Democratic-Republican | 1782–1861 |
| Peter Meijer | 2021–2023 | Michigan | Republican | 1988–present |
| George de Rue Meiklejohn | 1893–1897 | Nebraska | Republican | 1857–1929 |
| Charlie Melançon | 2005–2011 | Louisiana | Democratic | 1947–present |
| John Melcher | 1969–1977 | Montana | Democratic | 1924–2018 |
| David B. Mellish | 1873–1874 | New York | Republican | 1831–1874 |
| Richard Menefee | 1837–1839 | Kentucky | Whig | 1809–1841 |
| Bob Menendez | 1993–2006 | New Jersey | Democratic | 1954–present |
| Franklin Menges | 1925–1931 | Pennsylvania | Republican | 1858–1956 |
| John W. Menzies | 1861–1863 | Kentucky | Unionist | 1819–1897 |
| Charles F. Mercer | 1817–1823 | Virginia | Federalist | 1778–1858 |
| 1823–1825 | Democratic-Republican | |||
| 1825–1837 | National Republican | |||
| 1837–1839 | Whig | |||
| David Henry Mercer | 1893–1903 | Nebraska | Republican | 1857–1919 |
| John Francis Mercer | 1792–1794 | Maryland | Anti-Administration | 1759–1821 |
| Ulysses Mercur | 1865-1872 | Pennsylvania | Republican | 1818–1887 |
| Elisha E. Meredith | 1891–1897 | Virginia | Democratic | 1848–1900 |
| David Meriwether | 1802–1807 | Georgia | Democratic-Republican | 1755–1822 |
| James Meriwether | 1825–1827 | Georgia | Democratic | 1789–1854 |
| James Archibald Meriwether | 1841–1843 | Georgia | Whig | 1806–1852 |
| Clinton L. Merriam | 1871–1875 | New York | Republican | 1824–1900 |
| William Matthews Merrick | 1871–1873 | Maryland | Democratic | 1818–1889 |
| D. Bailey Merrill | 1953–1955 | Indiana | Republican | 1912–1993 |
| Orsamus Cook Merrill | 1817–1820 | Vermont | Democratic-Republican | 1775–1865 |
| Truman A. Merriman | 1885–1889 | New York | Democratic | 1839–1892 |
| Edwin A. Merritt | 1912–1914 | New York | Republican | 1860–1914 |
| Matthew J. Merritt | 1935–1945 | New York | Democratic | 1895–1946 |
| Samuel A. Merritt | 1871–1873 | Idaho | Democratic | 1827–1910 |
| Schuyler Merritt | 1917–1931 1933–1937 | Connecticut | Republican | 1853–1953 |
| Chester E. Merrow | 1943–1963 | New Hampshire | Republican | 1906–1974 |
| Orange Merwin | 1825–1829 | Connecticut | National Republican | 1777–1853 |
| William S. Mesick | 1897–1901 | Michigan | Republican | 1856–1942 |
| Thomas Meskill | 1967–1971 | Connecticut | Republican | 1928–2007 |
| Luke Messer | 2013–2019 | Indiana | Republican | 1969–present |
| Arunah Metcalf | 1811–1813 | New York | Democratic–Republican | 1771–1848 |
| Jack Metcalf | 1995–2001 | Washington | Republican | 1927–2007 |
| Lee Metcalf | 1953–1961 | Montana | Democratic | 1911–1978 |
| Victor H. Metcalf | 1899–1904 | California | Republican | 1853–1936 |
| Henry B. Metcalfe | 1875–1877 | New York | Democratic | 1805–1881 |
| Lyne Metcalfe | 1877–1879 | Missouri | Republican | 1822–1906 |
| Ralph H. Metcalfe | 1971–1978 | Illinois | Democratic | 1910–1978 |
| Thomas Metcalfe | 1819–1821 | Kentucky | Federalist | 1780–1855 |
| 1821–1825 | Democratic-Republican | |||
| 1825–1828 | National Republican | |||
| Herman A. Metz | 1913–1915 | New York | Democratic | 1867–1934 |
| Adolph Meyer | 1891–1908 | Louisiana | Democratic | 1842–1908 |
| Herbert A. Meyer | 1947–1950 | Kansas | Republican | 1886–1950 |
| John Ambrose Meyer | 1941–1943 | Maryland | Democratic | 1899–1969 |
| William H. Meyer | 1959–1961 | Vermont | Democratic | 1914–1983 |
| Benjamin F. Meyers | 1871-1873 | Pennsylvania | Democratic | 1833–1918 |
| Jan Meyers | 1985–1997 | Kansas | Republican | 1928–2019 |
| Helen Stevenson Meyner | 1975–1979 | New Jersey | Democratic | 1929–1997 |
| Edward Mezvinsky | 1973–1977 | Iowa | Democratic | 1937–present |
| Dan Mica | 1979–1989 | Florida | Democratic | 1944–present |
| John Mica | 1993–2017 | Florida | Republican | 1943–present |
| M. Alfred Michaelson | 1921–1931 | Illinois | Republican | 1878–1949 |
| Anthony Michalek | 1905–1907 | Illinois | Republican | 1878–1916 |
| Mike Michaud | 2003–2015 | Maine | Democratic | 1955–present |
| Robert H. Michel | 1957–1995 | Illinois | Republican | 1923–2017 |
| Earl C. Michener | 1919–1933 1935–1951 | Michigan | Republican | 1876–1957 |
| J. Ross Mickey | 1901–1903 | Illinois | Democratic | 1856–1928 |
| Ner Middleswarth | 1853-1855 | Pennsylvania | Whig | 1783–1865 |
| George Middleton | 1863–1865 | New Jersey | Democratic | 1800–1888 |
| Henry Middleton | 1815–1819 | South Carolina | Democratic-Republican | 1770–1846 |
| Robert W. Miers | 1897–1905 | Indiana | Democratic | 1848–1930 |
| Barbara Mikulski | 1977–1987 | Maryland | Democratic | 1936–present |
| Abner Mikva | 1969–1973 1975–1979 | Illinois | Democratic | 1926–2016 |
| Frederick Miles | 1879–1883 1889–1891 | Connecticut | Republican | 1815–1896 |
| John E. Miles | 1949–1951 | New Mexico | Democratic | 1884–1971 |
| Joshua W. Miles | 1895–1897 | Maryland | Democratic | 1858–1929 |
| William Porcher Miles | 1857–1860 | South Carolina | Democratic | 1822–1899 |
| Dale Milford | 1973–1979 | Texas | Democratic | 1926–1997 |
| Charles D. Millard | 1931-1937 | New York | Republican | 1873–1944 |
| Stephen C. Millard | 1885-1887 | New York | Republican | 1841–1914 |
| John Milledge | 1792–1793 | Georgia | Anti-Administration | 1757–1818 |
| 1795–1799 1801–1802 | Democratic-Republican | |||
| John Millen | 1843 | Georgia | Democratic | 1804–1843 |
| Juanita Millender-McDonald | 1996–2007 | California | Democratic | 1938–2007 |
| Arthur L. Miller | 1943–1959 | Nebraska | Republican | 1892–1967 |
| Brad Miller | 2003–2013 | North Carolina | Democratic | 1953–present |
| Candice Miller | 2003–2017 | Michigan | Republican | 1954–present |
| Clarence B. Miller | 1909–1919 | Minnesota | Republican | 1872–1922 |
| Clarence E. Miller | 1967–1993 | Ohio | Republican | 1917–2011 |
| Clem Miller | 1959–1962 | California | Democratic | 1916–1962 |
| Dan Miller | 1993–2003 | Florida | Republican | 1942–present |
| Daniel F. Miller | 1850–1851 | Iowa | Whig | 1814–1895 |
| Daniel H. Miller | 1823–1825 | Pennsylvania | Democratic-Republican | ????–1846 |
| 1825–1831 | Democratic | |||
| Edward E. Miller | 1923–1925 | Illinois | Republican | 1880–1946 |
| Edward T. Miller | 1947–1959 | Maryland | Republican | 1895–1968 |
| Gary Miller | 1999–2015 | California | Republican | 1948–present |
| George Funston Miller | 1865–1869 | Pennsylvania | Republican | 1809–1885 |
| George P. Miller | 1945–1973 | California | Democratic | 1891–1982 |
| George Miller | 1975–2015 | California | Democratic | 1945–present |
| Howard Shultz Miller | 1953–1955 | Kansas | Democratic | 1879–1970 |
| James Francis Miller | 1883–1887 | Texas | Democratic | 1830–1902 |
| James Monroe Miller | 1899–1911 | Kansas | Republican | 1852–1926 |
| Jeff Miller | 2001–2017 | Florida | Republican | 1959–present |
| Jesse Miller | 1833-1836 | Pennsylvania | Democratic | 1800–1850 |
| John Miller | 1825–1827 | New York | National Republican | 1774–1862 |
| John Miller | 1837–1843 | Missouri | Democratic | 1781–1846 |
| John E. Miller | 1931–1937 | Arkansas | Democratic | 1888–1981 |
| John Franklin Miller | 1917–1931 | Washington | Republican | 1862–1936 |
| John G. Miller | 1851–1855 | Missouri | Whig | 1812–1856 |
| 1855–1856 | Oppositionist | |||
| John K. Miller | 1847–1851 | Ohio | Democratic | 1819–1863 |
| John Miller | 1985–1993 | Washington | Republican | 1938–2017 |
| Joseph Miller | 1857–1859 | Ohio | Democratic | 1819–1862 |
| Killian Miller | 1855–1857 | New York | Whig | 1785–1859 |
| Louis E. Miller | 1943–1945 | Missouri | Republican | 1899–1952 |
| Lucas M. Miller | 1891–1893 | Wisconsin | Democratic | 1824–1902 |
| Morris S. Miller | 1813–1815 | New York | Federalist | 1779–1824 |
| Orrin L. Miller | 1895–1897 | Kansas | Republican | 1856–1926 |
| Pleasant Moorman Miller | 1809–1811 | Tennessee | Democratic-Republican | ????–1849 |
| Rutger B. Miller | 1836–1837 | New York | Democratic | 1805–1877 |
| Samuel F. Miller | 1863-1865 1875-1877 | New York | Republican | 1827–1892 |
| Samuel H. Miller | 1881-1885 1915-1917 | Pennsylvania | Republican | 1840–1918 |
| Smith Miller | 1853–1857 | Indiana | Democratic | 1804–1872 |
| Stephen Decatur Miller | 1817–1819 | South Carolina | Democratic-Republican | 1787–1838 |
| Thomas B. Miller | 1942-1945 | Pennsylvania | Republican | 1896–1976 |
| Thomas E. Miller | 1890–1891 | South Carolina | Republican | 1849–1938 |
| Thomas W. Miller | 1915–1917 | Delaware | Republican | 1886–1973 |
| Ward Miller | 1960–1961 | Ohio | Republican | 1902–1984 |
| Warner Miller | 1879–1881 | New York | Republican | 1838–1918 |
| Warren Miller | 1895–1899 | West Virginia | Republican | 1847–1920 |
| William E. Miller | 1951–1965 | New York | Republican | 1914–1983 |
| William H. Miller | 1863–1865 | Pennsylvania | Democratic | 1829–1870 |
| William J. Miller | 1939–1941 1943–1945 1947–1949 | Connecticut | Republican | 1899–1950 |
| William S. Miller | 1845-1847 | New York | American | 1793–1854 |
| Jacob L. Milligan | 1920–1921 1923–1935 | Missouri | Democratic | 1889–1951 |
| John J. Milligan | 1831–1839 | Delaware | Whig | 1795–1875 |
| Charles W. Milliken | 1873–1877 | Kentucky | Democratic | 1827–1915 |
| Seth L. Milliken | 1883–1897 | Maine | Republican | 1831–1897 |
| William H. Milliken Jr. | 1959-1965 | Pennsylvania | Republican | 1897–1969 |
| Charles S. Millington | 1909-1911 | New York | Republican | 1855–1913 |
| Daniel W. Mills | 1897–1899 | Illinois | Republican | 1838–1904 |
| Elijah H. Mills | 1815–1819 | Massachusetts | Federalist | 1776–1829 |
| Newt V. Mills | 1937–1943 | Louisiana | Democratic | 1899–1996 |
| Ogden L. Mills | 1921–1927 | New York | Republican | 1884–1937 |
| Roger Q. Mills | 1873–1892 | Texas | Democratic | 1832–1911 |
| Wilbur Mills | 1939–1977 | Arkansas | Democratic | 1909–1992 |
| William Oswald Mills | 1971–1973 | Maryland | Republican | 1924–1973 |
| John S. Millson | 1849–1861 | Virginia | Democratic | 1808–1874 |
| Frank C. Millspaugh | 1921–1922 | Missouri | Republican | 1872–1947 |
| William Millward | 1855–1857 | Pennsylvania | Oppositionist | 1822–1871 |
| 1859–1861 | Republican | |||
| Alfred Milnes | 1895–1897 | Michigan | Republican | 1844–1916 |
| William Milnes Jr. | 1870–1871 | Virginia | Conservative | 1827–1889 |
| James Milnor | 1811–1813 | Pennsylvania | Federalist | 1773–1845 |
| William Milnor | 1807–1811 1815–1817 1819–1822 | Pennsylvania | Federalist | 1769–1848 |
| Daniel F. Minahan | 1919–1921 1923–1925 | New Jersey | Democratic | 1877–1947 |
| Ahiman Louis Miner | 1851–1853 | Vermont | Whig | 1804–1886 |
| Charles Miner | 1825–1829 | Pennsylvania | National Republican | 1780–1865 |
| Henry C. Miner | 1895-1897 | New York | Democratic | 1842–1900 |
| Phineas Miner | 1834–1835 | Connecticut | National Republican | 1777–1839 |
| Norman Mineta | 1975–1995 | California | Democratic | 1931–2022 |
| David Minge | 1993–2001 | Minnesota | Democratic-Farmer-Labor | 1942–present |
| Joseph Minish | 1963–1985 | New Jersey | Democratic | 1916–2007 |
| Patsy Mink | 1965–1977 1990–2002 | Hawaii | Democratic | 1927–2002 |
| Walt Minnick | 2009–2011 | Idaho | Democratic | 1942–present |
| Edward S. Minor | 1895–1907 | Wisconsin | Republican | 1840-1924 |
| William Edwin Minshall Jr. | 1955–1974 | Ohio | Republican | 1911-1990 |
| Alexander Mitchell | 1871–1875 | Wisconsin | Democratic | 1817-1887 |
| Alexander C. Mitchell | 1911 | Kansas | Republican | 1860-1911 |
| Anderson Mitchell | 1842–1843 | North Carolina | Whig | 1800-1876 |
| Arthur Wergs Mitchell | 1935–1943 | Illinois | Democratic | 1883-1968 |
| Charles F. Mitchell | 1837–1841 | New York | Whig | 1806–1865 |
| Charles L. Mitchell | 1883–1887 | Connecticut | Democratic | 1844–1890 |
| Donald J. Mitchell | 1973–1983 | New York | Republican | 1923–2003 |
| E. A. Mitchell | 1947–1949 | Indiana | Republican | 1910-1979 |
| George Edward Mitchell | 1823–1825 | Maryland | Democratic-Republican | 1781-1832 |
| 1825–1827 1829–1832 | Democratic | |||
| Harlan Erwin Mitchell | 1958–1961 | Georgia | Democratic | 1924–2011 |
| Harry Mitchell | 2007–2011 | Arizona | Democratic | 1940–present |
| Henry Mitchell | 1833–1835 | New York | Democratic | 1784–1856 |
| Hugh Mitchell | 1949–1953 | Washington | Democratic | 1907–1996 |
| James Coffield Mitchell | 1825–1829 | Tennessee | Democratic | 1786–1843 |
| James S. Mitchell | 1821–1823 | Pennsylvania | Democratic-Republican | 1784–1844 |
| John Mitchell | 1825-1829 | Pennsylvania | Democratic | 1781–1849 |
| John I. Mitchell | 1877-1881 | Pennsylvania | Republican | 1838–1907 |
| John Joseph Mitchell | 1910–1911 1913–1915 | Massachusetts | Democratic | 1873–1925 |
| John L. Mitchell | 1891–1893 | Wisconsin | Democratic | 1842–1904 |
| John M. Mitchell | 1896-1899 | New York | Republican | 1858–1905 |
| John Ridley Mitchell | 1931–1939 | Tennessee | Democratic | 1877–1962 |
| Nahum Mitchell | 1803–1805 | Massachusetts | Federalist | 1769–1853 |
| Parren Mitchell | 1971–1987 | Maryland | Democratic | 1922–2007 |
| Paul Mitchell | 2017–2020 | Michigan | Republican | 1956–2021 |
| 2020–2021 | Independent | |||
| Robert Mitchell | 1833–1835 | Ohio | Democratic | 1778–1848 |
| Thomas R. Mitchell | 1821–1823 | South Carolina | Democratic-Republican | 1783–1837 |
| 1825–1829 1831–1833 | Democratic | |||
| William Mitchell | 1861–1863 | Indiana | Republican | 1807–1865 |
| Samuel L. Mitchill | 1801-1804 1810-1813 | New York | Democratic–Republican | 1764–1831 |
| Chester L. Mize | 1965–1971 | Kansas | Republican | 1917–1994 |
| Wilmer Mizell | 1969–1975 | North Carolina | Republican | 1930–1999 |
| Joe Moakley | 1973–2001 | Massachusetts | Democratic | 1927–2001 |
| Carlton Mobley | 1932–1933 | Georgia | Democratic | 1906–1981 |
| Walter H. Moeller | 1959–1963 1965–1967 | Ohio | Democratic | 1910–1999 |
| Seth C. Moffatt | 1885–1887 | Michigan | Republican | 1841–1887 |
| John Moffet | 1869-1869 | Pennsylvania | Democratic | 1831–1884 |
| Toby Moffett | 1975–1983 | Connecticut | Democratic | 1944–present |
| Hosea Moffitt | 1813–1817 | New York | Federalist | 1757–1825 |
| John H. Moffitt | 1887-1891 | New York | Republican | 1843-1926 |
| Guy Molinari | 1981–1989 | New York | Republican | 1928–2018 |
| Susan Molinari | 1990–1997 | New York | Republican | 1958–present |
| Marc Molinaro | 2023–2025 | New York | Republican | 1975–present |
| Alan Mollohan | 1983–2011 | West Virginia | Democratic | 1943–present |
| Bob Mollohan | 1953–1957 1969–1983 | West Virginia | Democratic | 1909–1999 |
| Richard S. Molony | 1851–1853 | Illinois | Democratic | 1811–1891 |
| John S. Monagan | 1959–1973 | Connecticut | Democratic | 1911–2005 |
| Joseph P. Monaghan | 1933–1937 | Montana | Democratic | 1906–1985 |
| James G. Monahan | 1919–1921 | Wisconsin | Republican | 1855–1923 |
| Louis Monast | 1927–1929 | Rhode Island | Republican | 1863–1936 |
| Frank W. Mondell | 1895–1897 1899–1923 | Wyoming | Republican | 1860–1939 |
| Robert Monell | 1819–1821 1829–1831 | New York | Democratic-Republican | 1786–1860 |
| Hernando Money | 1875–1885 1893–1897 | Mississippi | Democratic | 1839–1912 |
| B. J. Monkiewicz | 1939–1941 1943–1945 | Connecticut | Republican | 1898–1971 |
| James Monroe | 1839-1841 | New York | Whig | 1799–1870 |
| James Monroe | 1871–1881 | Ohio | Republican | 1821–1898 |
| Mike Monroney | 1939–1951 | Oklahoma | Democratic | 1902–1980 |
| David Smith Monson | 1985–1987 | Utah | Republican | 1945–present |
| Andrew J. Montague | 1913–1937 | Virginia | Democratic | 1862–1937 |
| Numa F. Montet | 1929–1937 | Louisiana | Democratic | 1892–1985 |
| Alexander B. Montgomery | 1887–1895 | Kentucky | Democratic | 1837–1910 |
| Daniel Montgomery Jr. | 1807–1809 | Pennsylvania | Democratic-Republican | 1765–1831 |
| John Montgomery | 1807–1811 | Maryland | Democratic-Republican | 1764–1828 |
| John Gallagher Montgomery | 1857 | Pennsylvania | Democratic | 1805–1857 |
| Samuel J. Montgomery | 1925–1927 | Oklahoma | Republican | 1896–1957 |
| Sonny Montgomery | 1967–1997 | Mississippi | Democratic | 1920–2006 |
| Thomas Montgomery | 1813–1815 1820–1823 | Kentucky | Democratic-Republican | 1779–1828 |
| William Montgomery | 1793–1795 | Pennsylvania | Anti-Administration | 1736–1816 |
| William Montgomery | 1835–1841 | North Carolina | Democratic | 1789–1844 |
| William Montgomery | 1857–1861 | Pennsylvania | Democratic | 1818–1870 |
| Joseph Montoya | 1957–1964 | New Mexico | Democratic | 1915–1978 |
| Néstor Montoya | 1921–1923 | New Mexico | Republican | 1862–1923 |
| James M. Moody | 1901–1903 | North Carolina | Republican | 1858–1903 |
| Jim Moody | 1983–1993 | Wisconsin | Democratic | 1935–2019 |
| Malcolm A. Moody | 1899–1903 | Oregon | Republican | 1854–1925 |
| William Henry Moody | 1895–1902 | Massachusetts | Republican | 1853-1917 |
| John A. Moon | 1897–1921 | Tennessee | Democratic | 1855–1921 |
| John W. Moon | 1893–1895 | Michigan | Republican | 1836–1898 |
| Reuben Moon | 1903–1913 | Pennsylvania | Republican | 1847–1919 |
| Alex Mooney | 2015–2025 | West Virginia | Republican | 1971–present |
| Charles A. Mooney | 1919–1921 1923–1931 | Ohio | Democratic | 1879–1931 |
| William C. Mooney | 1915–1917 | Ohio | Republican | 1855–1918 |
| Allen F. Moore | 1921–1925 | Illinois | Republican | 1869–1945 |
| Andrew Moore | 1789–1795 | Virginia | Anti-Administration | 1752–1821 |
| 1795–1797 1804 | Democratic-Republican | |||
| Arch A. Moore Jr. | 1957–1969 | West Virginia | Republican | 1923–2015 |
| C. Ellis Moore | 1919–1933 | Ohio | Republican | 1884–1941 |
| Dennis Moore | 1999–2011 | Kansas | Democratic | 1945–2021 |
| Eliakim H. Moore | 1869–1871 | Ohio | Republican | 1812–1900 |
| Ely Moore | 1835–1839 | New York | Democratic | 1798–1860 |
| Gabriel Moore | 1821–1825 | Alabama | Democratic-Republican | 1785–1845 |
| 1825–1829 | Democratic | |||
| Heman A. Moore | 1843–1844 | Ohio | Democratic | 1809–1844 |
| Henry D. Moore | 1849–1853 | Pennsylvania | Whig | 1817–1887 |
| Henson Moore | 1975–1987 | Louisiana | Republican | 1939–present |
| Horace Ladd Moore | 1894–1895 | Kansas | Democratic | 1837–1914 |
| J. Hampton Moore | 1906–1920 | Pennsylvania | Republican | 1864–1950 |
| Jeese H. Moore | 1869–1873 | Illinois | Republican | 1817–1883 |
| John Moore | 1840–1843 1851–1853 | Louisiana | Whig | 1788–1867 |
| John M. Moore | 1905–1913 | Texas | Democratic | 1862–1940 |
| John William Moore | 1925–1929 1929–1933 | Kentucky | Democratic | 1877–1941 |
| Laban T. Moore | 1859–1861 | Kentucky | Oppositionist | 1829–1892 |
| Littleton W. Moore | 1887–1893 | Texas | Democratic | 1835–1911 |
| Nicholas R. Moore | 1803–1811 1813–1815 | Maryland | Democratic-Republican | 1756–1816 |
| Orren C. Moore | 1889–1891 | New Hampshire | Republican | 1839–1893 |
| Oscar F. Moore | 1855–1857 | Ohio | Republican | 1817–1885 |
| Paul J. Moore | 1927–1929 | New Jersey | Democratic | 1868–1938 |
| Robert Lee Moore | 1923–1925 | Georgia | Democratic | 1867–1940 |
| R. Walton Moore | 1919–1931 | Virginia | Democratic | 1859–1941 |
| Robert Moore | 1817-1821 | Pennsylvania | Democratic-Republican | 1778–1831 |
| Samuel Moore | 1818–1822 | Pennsylvania | Democratic-Republican | 1774–1861 |
| Samuel M. Moore | 1833–1835 | Virginia | National Republican | 1796–1875 |
| Sydenham Moore | 1857–1861 | Alabama | Democratic | 1817–1862 |
| Thomas Moore | 1801–1813 1815–1817 | South Carolina | Democratic-Republican | 1759–1822 |
| Thomas Love Moore | 1820–1823 | Virginia | Democratic-Republican | 17??–1862 |
| Thomas P. Moore | 1823–1825 | Kentucky | Democratic-Republican | 1797–1853 |
| 1825–1829 | Democratic | |||
| William Moore | 1867–1871 | New Jersey | Republican | 1810–1878 |
| William Robert Moore | 1881–1883 | Tennessee | Republican | 1830–1909 |
| William S. Moore | 1873-1875 | Pennsylvania | Republican | 1822–1877 |
| Tom Van Horn Moorehead | 1961–1963 | Ohio | Republican | 1898–1979 |
| Merrill Moores | 1915–1925 | Indiana | Republican | 1856–1929 |
| Carlos Moorhead | 1973–1997 | California | Republican | 1922–2011 |
| James K. Moorhead | 1859-1869 | Pennsylvania | Republican | 1806–1884 |
| William S. Moorhead | 1959-1981 | Pennsylvania | Democratic | 1923–1987 |
| Henry D. Moorman | 1927–1929 | Kentucky | Democratic | 1880–1939 |
| Edward C. Moran Jr. | 1933–1937 | Maine | Democratic | 1894–1967 |
| Jerry Moran | 1997–2011 | Kansas | Republican | 1954–present |
| Jim Moran | 1991–2015 | Virginia | Democratic | 1945–present |
| Albert P. Morano | 1951–1959 | Connecticut | Republican | 1908–1987 |
| Charles S. Morehead | 1847–1851 | Kentucky | Whig | 1802–1868 |
| James Turner Morehead | 1851–1853 | North Carolina | Whig | 1799–1875 |
| John H. Morehead | 1923–1935 | Nebraska | Democratic | 1861–1942 |
| John Motley Morehead II | 1909–1911 | North Carolina | Republican | 1866–1923 |
| Connie Morella | 1987–2003 | Maryland | Republican | 1931–present |
| Frank Morey | 1869–1876 | Louisiana | Republican | 1840–1890 |
| Henry Lee Morey | 1881–1884 1889–1891 | Ohio | Republican | 1841–1902 |
| Charles H. Morgan | 1875–1879 1883–1885 1893–1895 | Missouri | Democratic | 1842–1912 |
| 1909–1911 | Republican | |||
| Christopher Morgan | 1839-1843 | New York | Whig | 1808–1877 |
| Daniel Morgan | 1797–1799 | Virginia | Federalist | 1736–1802 |
| Dick T. Morgan | 1909–1920 | Oklahoma | Republican | 1853–1920 |
| Edwin B. Morgan | 1853-1859 | New York | Whig | 1806–1881 |
| George W. Morgan | 1867–1873 | Ohio | Democratic | 1820–1893 |
| James Morgan | 1811–1813 | New Jersey | Democratic-Republican | 1756–1822 |
| James B. Morgan | 1885–1891 | Mississippi | Democratic | 1833–1892 |
| John J. Morgan | 1821–1825 1834–1835 | New York | Democratic-Republican | 1770–1849 |
| Lewis L. Morgan | 1912–1917 | Louisiana | Democratic | 1876–1950 |
| Stephen Morgan | 1899–1905 | Ohio | Republican | 1854–1928 |
| Thomas E. Morgan | 1945-1977 | Pennsylvania | Democratic | 1906–1995 |
| William M. Morgan | 1921–1931 | Ohio | Republican | 1870–1935 |
| William S. Morgan | 1835–1839 | Virginia | Democratic | 1801–1878 |
| John M. Morin | 1913-1929 | Pennsylvania | Republican | 1868–1942 |
| Theodore L. Moritz | 1935-1937 | Pennsylvania | Democratic | 1892–1982 |
| Joseph L. Morphis | 1870–1873 | Mississippi | Republican | 1831–1913 |
| Daniel J. Morrell | 1867-1871 | Pennsylvania | Republican | 1821–1885 |
| Edward de Veaux Morrell | 1900–1907 | Pennsylvania | Republican | 1863–1917 |
| Anson Morrill | 1861–1863 | Maine | Republican | 1803–1887 |
| Edmund N. Morrill | 1883–1891 | Kansas | Republican | 1834–1909 |
| Justin S. Morrill | 1855–1867 | Vermont | Republican | 1810–1898 |
| Samuel P. Morrill | 1869–1871 | Maine | Republican | 1816–1892 |
| Calvary Morris | 1837–1843 | Ohio | Whig | 1798–1871 |
| Daniel Morris | 1863-1867 | New York | Republican | 1812–1889 |
| Edward Joy Morris | 1843–1845 1857–1861 | Pennsylvania | Whig | 1815–1881 |
| Isaac N. Morris | 1857–1861 | Illinois | Democratic | 1812–1879 |
| James R. Morris | 1861–1865 | Ohio | Democratic | 1819–1899 |
| Jonathan D. Morris | 1847–1851 | Ohio | Democratic | 1804–1875 |
| Joseph Morris | 1843–1847 | Ohio | Democratic | 1795–1854 |
| Joseph W. Morris | 1923–1925 | Kentucky | Democratic | 1879–1937 |
| Lewis R. Morris | 1797–1803 | Vermont | Federalist | 1760–1825 |
| Mathias Morris | 1835–1837 | Pennsylvania | National Republican | 1787–1839 |
| 1837–1839 | Whig | |||
| Page Morris | 1897–1903 | Minnesota | Republican | 1853–1924 |
| Samuel W. Morris | 1837-1841 | Pennsylvania | Democratic | 1786–1847 |
| Thomas Morris | 1801-1803 | New York | Federalist | 1771–1849 |
| Thomas G. Morris | 1959–1969 | New Mexico | Democratic | 1919–2016 |
| Toby Morris | 1947–1953 1957–1961 | Oklahoma | Democratic | 1899–1973 |
| Bruce Morrison | 1983–1991 | Connecticut | Democratic | 1944–present |
| Cameron A. Morrison | 1943–1945 | North Carolina | Democratic | 1869–1953 |
| George W. Morrison | 1850–1851 1853–1855 | New Hampshire | Democratic | 1809–1888 |
| James H. Morrison | 1943–1967 | Louisiana | Democratic | 1908–2000 |
| James L. D. Morrison | 1856–1857 | Illinois | Democratic | 1816–1888 |
| John Alexander Morrison | 1851-1853 | Pennsylvania | Democratic | 1814–1904 |
| Martin A. Morrison | 1909–1917 | Indiana | Democratic | 1862–1944 |
| Sid Morrison | 1981–1993 | Washington | Republican | 1933–present |
| William R. Morrison | 1863–1865 1873–1887 | Illinois | Democratic | 1824–1909 |
| John Morrissey | 1867-1871 | New York | Democratic | 1831–1878 |
| Jeremiah Morrow | 1803–1813 | Ohio | Democratic-Republican | 1771–1852 |
| 1840–1843 | Whig | |||
| John Morrow | 1805–1809 | Virginia | Democratic-Republican | N/A |
| John Morrow | 1923–1929 | New Mexico | Democratic | 1865–1935 |
| William W. Morrow | 1885–1891 | California | Republican | 1843–1929 |
| Elijah A. Morse | 1889–1897 | Massachusetts | Republican | 1841–1898 |
| Elmer A. Morse | 1907–1913 | Wisconsin | Republican | 1870–1945 |
| F. Bradford Morse | 1961–1972 | Massachusetts | Republican | 1921–1994 |
| Freeman H. Morse | 1843–1845 | Maine | Whig | 1807–1891 |
| 1857–1861 | Republican | |||
| Isaac E. Morse | 1844–1851 | Louisiana | Democratic | 1809–1866 |
| Leopold Morse | 1877–1885 1887–1889 | Massachusetts | Democratic | 1831–1892 |
| Oliver A. Morse | 1857-1859 | New York | Republican | 1815-1870 |
| Jeremiah Morton | 1849–1851 | Virginia | Whig | 1799–1878 |
| Levi P. Morton | 1879–1881 | New York | Republican | 1824–1920 |
| Marcus Morton | 1817–1821 | Massachusetts | Democratic-Republican | 1784–1864 |
| Rogers Morton | 1963–1971 | Maryland | Republican | 1914–1979 |
| Thruston Ballard Morton | 1947–1953 | Kentucky | Republican | 1907–1982 |
| Jonathan O. Moseley | 1805–1821 | Connecticut | Federalist | 1762–1838 |
| William A. Moseley | 1843-1847 | New York | Whig | 1798–1873 |
| Guy L. Moser | 1937-1943 | Pennsylvania | Democratic | 1886–1961 |
| Charles L. Moses | 1891–1897 | Georgia | Democratic | 1856–1910 |
| James Mosgrove | 1881-1883 | Pennsylvania | Greenbacker | 1821–1900 |
| Charles Adams Mosher | 1961–1977 | Ohio | Republican | 1906–1984 |
| Harold G. Mosier | 1937–1939 | Ohio | Democratic | 1889–1971 |
| Hunter H. Moss Jr. | 1913–1916 | West Virginia | Republican | 1874–1916 |
| J. McKenzie Moss | 1902–1903 | Kentucky | Republican | 1868–1929 |
| John E. Moss | 1953–1978 | California | Democratic | 1915–1997 |
| Ralph W. Moss | 1909–1917 | Indiana | Democratic | 1862–1919 |
| Gordon N. Mott | 1863–1864 | Nevada | Republican | 1812–1887 |
| James Mott | 1801–1805 | New Jersey | Democratic-Republican | 1739–1823 |
| James W. Mott | 1933–1945 | Oregon | Republican | 1883–1945 |
| Luther W. Mott | 1911–1923 | New York | Republican | 1874–1923 |
| Richard Mott | 1855–1859 | Ohio | Republican | 1804–1888 |
| Ronald M. Mottl | 1975–1983 | Ohio | Democratic | 1934–2023 |
| Morgan M. Moulder | 1949–1963 | Missouri | Democratic | 1904–1976 |
| Mace Moulton | 1845–1847 | New Hampshire | Democratic | 1796–1867 |
| Samuel W. Moulton | 1865–1867 | Illinois | Republican | 1821–1905 |
| 1881–1885 | Democratic | |||
| Grant E. Mouser | 1905–1909 | Ohio | Republican | 1868–1949 |
| Grant E. Mouser Jr. | 1929–1933 | Ohio | Republican | 1895–1943 |
| Robert L. Mouton | 1937–1941 | Louisiana | Democratic | 1892–1956 |
| William Moxley | 1909–1911 | Illinois | Republican | 1851–1938 |
| P. H. Moynihan | 1933–1935 | Illinois | Republican | 1869–1946 |
| Norman A. Mozley | 1895–1897 | Missouri | Republican | 1865–1922 |
| Robert J. Mrazek | 1983–1993 | New York | Democratic | 1945–present |
| Joseph Mruk | 1943-1945 | New York | Republican | 1903–1995 |
| Debbie Mucarsel-Powell | 2019–2021 | Florida | Democratic | 1971–present |
| Sydney E. Mudd I | 1890–1891 1897–1911 | Maryland | Republican | 1858–1911 |
| Sydney Emanuel Mudd II | 1915–1924 | Maryland | Republican | 1885–1924 |
| Francis Swaine Muhlenberg | 1828–1829 | Ohio | National Republican | 1795–1831 |
| Frederick Muhlenberg | 1789–1791 | Pennsylvania | Pro-Administration | 1750–1801 |
| 1791–1795 | Anti-Administration | |||
| 1795–1797 | Democratic-Republican | |||
| Frederick Augustus Muhlenberg | 1947–1949 | Pennsylvania | Republican | 1887–1980 |
| Henry Augustus Muhlenberg | 1853–1854 | Pennsylvania | Democratic | 1823–1854 |
| Henry A. P. Muhlenberg | 1829–1833 | Pennsylvania | Democratic | 1782–1844 |
| Peter Muhlenberg | 1789–1791 1793–1795 | Pennsylvania | Anti-Administration | 1746–1807 |
| 1799–1801 | Democratic-Republican | |||
| Michael Joseph Muldowney | 1933–1935 | Pennsylvania | Republican | 1889–1947 |
| Henry L. Muldrow | 1877–1885 | Mississippi | Democratic | 1837–1905 |
| William Oscar Mulkey | 1914–1915 | Alabama | Democratic | 1871–1943 |
| Nicholas Muller | 1877-1881 1883-1887 1899-1901 | New York | Democratic | 1836–1917 |
| Joseph Mullin | 1847-1849 | New York | Whig | 1811-1882 |
| Markwayne Mullin | 2013–2023 | Oklahoma | Republican | 1977–present |
| James Mullins | 1867–1869 | Tennessee | Republican | 1807-1873 |
| Abraham J. Multer | 1947-1967 | New York | Democratic | 1900–1986 |
| Mick Mulvaney | 2011-2017 | South Carolina | Republican | 1967–present |
| George Mumford | 1817–1818 | North Carolina | Democratic-Republican | ????–1818 |
| Gurdon S. Mumford | 1805-1811 | New York | Democratic–Republican | 1764–1831 |
| Walter M. Mumma | 1951-1961 | Pennsylvania | Republican | 1890–1961 |
| Karl Mundt | 1939–1948 | South Dakota | Republican | 1900–1974 |
| William Mungen | 1867–1871 | Ohio | Democratic | 1821–1887 |
| Luis Muñoz Rivera | 1911–1916 | Puerto Rico | Union | 1859–1916 |
| Thompson H. Murch | 1879–1883 | Maine | Greenbacker | 1838–1886 |
| Abe Murdock | 1933–1941 | Utah | Democratic | 1893–1979 |
| John R. Murdock | 1937–1953 | Arizona | Democratic | 1885–1972 |
| Victor Murdock | 1903–1915 | Kansas | Republican | 1871–1945 |
| William H. Murfree | 1813–1817 | North Carolina | Democratic-Republican | 1781–1827 |
| Charles Murphey | 1851–1853 | Georgia | Unionist | 1799–1861 |
| Arthur P. Murphy | 1905–1907 1909–1911 | Missouri | Republican | 1870–1914 |
| Austin Murphy | 1977–1995 | Pennsylvania | Democratic | 1927–2024 |
| B. Frank Murphy | 1919–1933 | Ohio | Republican | 1867–1938 |
| Chris Murphy | 2007–2013 | Connecticut | Democratic | 1973–present |
| Everett J. Murphy | 1895–1897 | Illinois | Republican | 1852–1922 |
| Henry C. Murphy | 1843-1845 1847-1849 | New York | Democratic | 1810–1882 |
| James J. Murphy | 1949-1953 | New York | Democratic | 1898–1962 |
| James William Murphy | 1907–1909 | Wisconsin | Democratic | 1858–1927 |
| Jeremiah H. Murphy | 1883–1887 | Iowa | Democratic | 1835–1893 |
| John Murphy | 1833–1835 | Alabama | Democratic | 1786–1841 |
| John M. Murphy | 1963–1981 | New York | Democratic | 1926–2015 |
| John W. Murphy | 1943–1946 | Pennsylvania | Democratic | 1902–1962 |
| Morgan F. Murphy | 1971–1981 | Illinois | Democratic | 1932–2016 |
| Oakes Murphy | 1895–1897 | Arizona | Republican | 1849–1908 |
| Patrick Murphy | 2007–2011 | Pennsylvania | Democratic | 1973–present |
| Patrick Murphy | 2013–2017 | Florida | Democratic | 1983–present |
| Scott Murphy | 2009–2011 | New York | Democratic | 1970–present |
| Tim Murphy | 2003–2017 | Pennsylvania | Republican | 1952–present |
| William T. Murphy | 1959–1971 | Illinois | Democratic | 1899–1978 |
| Ambrose S. Murray | 1855–1859 | New York | Whig | 1807–1885 |
| George W. Murray | 1893–1895 1896–1897 | South Carolina | Republican | 1853–1926 |
| James C. Murray | 1955–1957 | Illinois | Democratic | 1917–1999 |
| John Murray | 1817–1821 | Pennsylvania | Democratic-Republican | 1768–1834 |
| John L. Murray | 1837–1839 | Kentucky | Democratic | 1806–1842 |
| Reid F. Murray | 1939–1952 | Wisconsin | Republican | 1887–1952 |
| Robert Maynard Murray | 1883–1885 | Ohio | Democratic | 1841–1913 |
| Thomas Murray Jr. | 1821-1823 | Pennsylvania | Democratic-Republican | 1770–1823 |
| Tom J. Murray | 1943–1966 | Tennessee | Democratic | 1894–1971 |
| William Murray | 1851–1855 | New York | Democratic | 1803–1875 |
| William Francis Murray | 1911–1914 | Massachusetts | Democratic | 1881–1918 |
| William H. Murray | 1913–1917 | Oklahoma | Democratic | 1869–1956 |
| William Vans Murray | 1791–1795 | Maryland | Pro-Administration | 1760–1803 |
| 1795–1797 | Federalist | |||
| John Murtha | 1974–2010 | Pennsylvania | Democratic | 1932–2010 |
| Marilyn Musgrave | 2003–2009 | Colorado | Republican | 1949–present |
| Harry W. Musselwhite | 1933–1935 | Michigan | Democratic | 1868–1955 |
| Ray Musto | 1980–1981 | Pennsylvania | Democratic | 1929–2014 |
| Howard Mutchler | 1893–1895 | Pennsylvania | Democratic | 1859–1916 |
| William Mutchler | 1875–1877 1881–1885 1889–1893 | Pennsylvania | Democratic | 1831–1893 |
| Amos Myers | 1863–1865 | Pennsylvania | Republican | 1824–1893 |
| Francis J. Myers | 1939–1945 | Pennsylvania | Democratic | 1901–1956 |
| Gary A. Myers | 1975-1979 | Pennsylvania | Republican | 1937–2020 |
| John T. Myers | 1967–1997 | Indiana | Republican | 1927–2015 |
| Leonard Myers | 1863–1875 | Pennsylvania | Republican | 1827–1905 |
| Michael Myers | 1976–1980 | Pennsylvania | Democratic | 1943–present |
| William R. Myers | 1879–1881 | Indiana | Democratic | 1836–1907 |
| Sue Myrick | 1995–2013 | North Carolina | Republican | 1941–present |