Iowa was admitted to the Union on December 28, 1846, and elects United States senators to class 2 and class 3. The state's current U.S. senators are Republicans Chuck Grassley (serving since 1981) and Joni Ernst (serving since 2015). Chuck Grassley is Iowa's longest-serving senator (since 1981).
Class 2 Class 2 U.S. senators belong to the electoral cycle that has recently been contested in 2002, 2008, 2014, and 2020. The next election will be in 2026. | C | Class 3 Class 3 U.S. senators belong to the electoral cycle that has recently been contested in 2004, 2010, 2016, and 2022. The next election will be in 2028. | ||||||||||
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# | Senator | Party | Dates in office | Electoral history | T | T | Electoral history | Dates in office | Party | Senator | # | |
Vacant | Dec 28, 1846 – Dec 7, 1848 | Legislature failed to elect. [1] | — | 29th | — | Legislature failed to elect. [1] | Dec 28, 1846 – Dec 7, 1848 | Vacant | ||||
30th | ||||||||||||
1 | George W. Jones | Democratic | Dec 7, 1848 – Mar 3, 1859 | Elected in 1848. | 1 | 1 | Elected in 1848. | Dec 7, 1848 – Feb 22, 1855 | Democratic | Augustus C. Dodge | 1 | |
31st | 2 | Re-elected in 1849.Resigned to become U.S. Minister to Spain, having lost re-election. | ||||||||||
32nd | ||||||||||||
Re-elected in 1852.Lost renomination. | 2 | 33rd | ||||||||||
Feb 22, 1855 – Mar 3, 1855 | Vacant | |||||||||||
34th | 3 | Elected in 1855.Elected invalidated, as the Iowa Senate had not participated in it. | Mar 4, 1855 – Jan 5, 1857 | Free Soil | James Harlan | 2 | ||||||
Jan 5, 1857 – Jan 29, 1857 | Vacant | |||||||||||
Re-elected to finish his vacant term. | Jan 29, 1857 – May 15, 1865 | Republican | James Harlan | |||||||||
35th | ||||||||||||
2 | James W. Grimes | Republican | Mar 4, 1859 – Dec 6, 1869 | Elected in 1858. | 3 | 36th | ||||||
37th | 4 | Re-elected in 1860.Resigned to become U.S. Secretary of the Interior. | ||||||||||
38th | ||||||||||||
Re-elected in 1864.Resigned due to ill health. | 4 | 39th | ||||||||||
May 15, 1865 – Jan 13, 1866 | Vacant | |||||||||||
Elected to finish Harlan's term. [2] Lost nomination for the next term. | Jan 13, 1866 – Mar 3, 1867 | Republican | Samuel J. Kirkwood | 3 | ||||||||
40th | 5 | Elected in 1866. [3] Lost re-election. | Mar 4, 1867 – Mar 3, 1873 | Republican | James Harlan | 4 | ||||||
41st | ||||||||||||
Vacant | Dec 6, 1869 – Jan 18, 1870 | |||||||||||
3 | James B. Howell | Republican | Jan 18, 1870 – Mar 3, 1871 | Elected to finish Grimes's term.Retired. | ||||||||
4 | George G. Wright | Republican | Mar 4, 1871 – Mar 3, 1877 | Elected in 1870.Retired. | 5 | 42nd | ||||||
43rd | 6 | Elected in 1872. [4] | Mar 4, 1873 – Aug 4, 1908 | Republican | William B. Allison | 5 | ||||||
44th | ||||||||||||
5 | Samuel J. Kirkwood | Republican | Mar 4, 1877 – Mar 7, 1881 | Elected in 1876 or 1877.Resigned to become U.S. Secretary of the Interior. | 6 | 45th | ||||||
46th | 7 | Re-elected in 1878. [5] | ||||||||||
47th | ||||||||||||
6 | James W. McDill | Republican | Mar 8, 1881 – Mar 3, 1883 | Appointed to continue Kirkwood's term. Elected in 1882 to finish Kirkwood's term. [6] Retired. | ||||||||
7 | James F. Wilson | Republican | Mar 4, 1883 – Mar 3, 1895 | Elected in 1882. [7] | 7 | 48th | ||||||
49th | 8 | Re-elected in 1884. [8] | ||||||||||
50th | ||||||||||||
Re-elected in 1888.Retired. | 8 | 51st | ||||||||||
52nd | 9 | Re-elected in 1890. [9] | ||||||||||
53rd | ||||||||||||
8 | John H. Gear | Republican | Mar 4, 1895 – Jul 14, 1900 | Elected in 1894. [10] Re-elected in 1900, [11] but died. | 9 | 54th | ||||||
55th | 10 | Re-elected in 1896. [12] | ||||||||||
56th | ||||||||||||
Vacant | Jul 14, 1900 – Aug 22, 1900 | |||||||||||
9 | Jonathan P. Dolliver | Republican | Aug 22, 1900 – Oct 15, 1910 | Appointed to finish Gear's term. | ||||||||
Appointed to begin the vacant term. Elected in 1902 to finish the vacant term. [13] | 10 | 57th | ||||||||||
58th | 11 | Re-elected in 1902. [14] Renominated in 1908 but died before the general election. | ||||||||||
59th | ||||||||||||
Re-elected in 1907.Died. | 11 | 60th | ||||||||||
Aug 4, 1908 – Nov 24, 1908 | Vacant | |||||||||||
Elected to finish Allison's term. | Nov 24, 1908 – Jul 30, 1926 | Republican | Albert B. Cummins | 6 | ||||||||
61st | 12 | Re-elected in 1909. | ||||||||||
Vacant | Oct 15, 1910 – Nov 12, 1910 | |||||||||||
10 | Lafayette Young | Republican | Nov 12, 1910 – Apr 11, 1911 | Appointed to continue Dolliver's term.Lost election to finish Dolliver's term. | ||||||||
62nd | ||||||||||||
11 | William S. Kenyon | Republican | Apr 12, 1911 – Feb 24, 1922 | Elected to finish Dolliver's term. | ||||||||
Re-elected in 1913. | 12 | 63rd | ||||||||||
64th | 13 | Re-elected in 1914. | ||||||||||
65th | ||||||||||||
Re-elected in 1918.Resigned to become Judge of the U.S. Court of Appeals. | 13 | 66th | ||||||||||
67th | 14 | Re-elected in 1920.Lost renomination, then died. | ||||||||||
12 | Charles A. Rawson | Republican | Feb 24, 1922 – Dec 1, 1922 | Appointed to continue Kenyon's term.Retired when his successor was elected. | ||||||||
13 | Smith W. Brookhart | Republican | Dec 1, 1922 – Apr 12, 1926 | Elected to finish Kenyon's term. | ||||||||
68th | ||||||||||||
Re-elected in 1924.Lost election challenge. | 14 | 69th | ||||||||||
14 | Daniel F. Steck | Democratic | Apr 12, 1926 – Mar 3, 1931 | Successfully challenged his predecessor's election.Lost re-election. | ||||||||
Jul 30, 1926 – Aug 7, 1926 | Vacant | |||||||||||
Appointed to continue Cummins's term. Elected in 1926 to finish Cummins's term. [15] Retired. | Aug 7, 1926 – Mar 3, 1927 | Republican | David W. Stewart | 7 | ||||||||
70th | 15 | Elected in 1926.Lost renomination and then lost re-election as an Independent. | Mar 4, 1927 – Mar 3, 1933 | Republican | Smith W. Brookhart | 8 | ||||||
71st | ||||||||||||
15 | L. J. Dickinson | Republican | Mar 4, 1931 – Jan 3, 1937 | Elected in 1930.Lost re-election. | 15 | 72nd | ||||||
73rd | 16 | Elected in 1932.Died. | Mar 4, 1933 – Jul 16, 1936 | Democratic | Louis Murphy | 9 | ||||||
74th | ||||||||||||
Jul 16, 1936 – Nov 3, 1936 | Vacant | |||||||||||
Elected to finish Murphy's term. | Nov 3, 1936 – Jan 3, 1945 | Democratic | Guy Gillette | 10 | ||||||||
16 | Clyde L. Herring | Democratic | Jan 3, 1937 – Jan 3, 1943 | Elected in 1936. Did not take seat until Jan 15, 1937 in order to remain Governor of Iowa.Lost re-election. | 16 | 75th | ||||||
76th | 17 | Re-elected in 1938.Lost re-election. | ||||||||||
77th | ||||||||||||
17 | George A. Wilson | Republican | Jan 3, 1943 – Jan 3, 1949 | Elected in 1942. Did not take seat until Jan 14, 1943 in order to remain Governor of Iowa.Lost re-election. | 17 | 78th | ||||||
79th | 18 | Elected in 1944. | Jan 3, 1945 – Jan 3, 1969 | Republican | Bourke B. Hickenlooper | 11 | ||||||
80th | ||||||||||||
18 | Guy Gillette | Democratic | Jan 3, 1949 – Jan 3, 1955 | Elected in 1948.Lost re-election. | 18 | 81st | ||||||
82nd | 19 | Re-elected in 1950. | ||||||||||
83rd | ||||||||||||
19 | Thomas E. Martin | Republican | Jan 3, 1955 – Jan 3, 1961 | Elected in 1954.Retired. | 19 | 84th | ||||||
85th | 20 | Re-elected in 1956. | ||||||||||
86th | ||||||||||||
20 | Jack Miller | Republican | Jan 3, 1961 – Jan 3, 1973 | Elected in 1960. | 20 | 87th | ||||||
88th | 21 | Re-elected in 1962 Retired. | ||||||||||
89th | ||||||||||||
Re-elected in 1966.Lost re-election. | 21 | 90th | ||||||||||
91st | 22 | Elected in 1968.Retired. | Jan 3, 1969 – Jan 3, 1975 | Democratic | Harold Hughes | 12 | ||||||
92nd | ||||||||||||
21 | Dick Clark | Democratic | Jan 3, 1973 – Jan 3, 1979 | Elected in 1972.Lost re-election. | 22 | 93rd | ||||||
94th | 23 | Elected in 1974.Lost re-election. | Jan 3, 1975 – Jan 3, 1981 | Democratic | John Culver | 13 | ||||||
95th | ||||||||||||
22 | Roger Jepsen | Republican | Jan 3, 1979 – Jan 3, 1985 | Elected in 1978.Lost re-election. | 23 | 96th | ||||||
97th | 24 | Elected in 1980. | Jan 3, 1981 – present | Republican | Chuck Grassley | 14 | ||||||
98th | ||||||||||||
23 | Tom Harkin | Democratic | Jan 3, 1985 – Jan 3, 2015 | Elected in 1984. | 24 | 99th | ||||||
100th | 25 | Re-elected in 1986. | ||||||||||
101st | ||||||||||||
Re-elected in 1990. | 25 | 102nd | ||||||||||
103rd | 26 | Re-elected in 1992. | ||||||||||
104th | ||||||||||||
Re-elected in 1996. | 26 | 105th | ||||||||||
106th | 27 | Re-elected in 1998. | ||||||||||
107th | ||||||||||||
Re-elected in 2002. | 27 | 108th | ||||||||||
109th | 28 | Re-elected in 2004. | ||||||||||
110th | ||||||||||||
Re-elected in 2008 Retired. | 28 | 111th | ||||||||||
112th | 29 | Re-elected in 2010. | ||||||||||
113th | ||||||||||||
24 | Joni Ernst | Republican | Jan 3, 2015 – present | Elected in 2014. | 29 | 114th | ||||||
115th | 30 | Re-elected in 2016. | ||||||||||
116th | ||||||||||||
Re-elected in 2020. | 30 | 117th | ||||||||||
118th | 31 | Re-elected in 2022. | ||||||||||
119th | ||||||||||||
To be determined in the 2026 election. | 31 | 120th | ||||||||||
121st | 32 | To be determined in the 2028 election. | ||||||||||
# | Senator | Party | Years in office | Electoral history | T | C | T | Electoral history | Years in office | Party | Senator | # |
Class 2 | Class 3 |
Charles Ernest Grassley is an American politician serving as the senior United States senator from Iowa, having held the seat since 1981. Grassley was first elected to the Senate in 1980 and has been reelected seven times. As of 2024, he is the oldest senator at 91 years old, and is the longest-serving Republican in Congressional history and the sixth-longest-serving U.S. senator in history.
Since Iowa became a U.S. state in 1846, it has sent congressional delegations to the United States Senate and United States House of Representatives. Each state elects two senators to serve for six years, and members of the House to two-year terms. Before becoming a state, the Iowa Territory elected a non-voting delegate at-large to Congress from 1838 to 1846.
The 2010 United States Senate election in Iowa was held on November 2, 2010, alongside other elections to the United States Senate in other states as well as elections to the United States House of Representatives and various state and local elections in Iowa. The party primary elections were held on June 8, 2010. Incumbent Republican U.S. Senator Chuck Grassley won reelection to a sixth term. This was the first time since 1986 where the losing Democratic United States Senate nominee carried any of the counties in Iowa for this seat.
The 1848–49 United States Senate elections were held on various dates in various states. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1848 and 1849, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the senators in Class 3.
The 1902–03 United States Senate elections were held on various dates in various states. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1902 and 1903, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the senators in Class 3.
The 1882–83 United States Senate elections were held on various dates in various states. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1882 and 1883, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the senators in Class 2.
The 1866–67 United States Senate elections were held on various dates in various states. As these U.S. Senate elections were prior to the ratification of the Seventeenth Amendment in 1913, senators were chosen by state legislatures. Senators were elected over a wide range of time throughout 1866 and 1867, and a seat may have been filled months late or remained vacant due to legislative deadlock. In these elections, terms were up for the senators in Class 3.
The 1986 United States Senate election in Iowa was held November 4, 1986. Incumbent Republican United States Senator Chuck Grassley won re-election to a second term, defeating Democratic nominee, attorney John P. Roehrick in a landslide. This would be the last time that Grassley lost a county until 2010 when Roxanne Conlin flipped Johnson County.
The 1980 United States Senate election in Iowa was held on November 4, 1980. Incumbent Democratic United States Senator John Culver ran for reelection to a second term, but lost to Republican nominee Chuck Grassley, the United States Congressman from Iowa's 3rd congressional district. This election marked the beginning of eight consecutive victories for Grassley in the Senate. It remains the closest election of his Senate career.
The 2016 United States Senate election in Iowa was held November 8, 2016, to elect a member of the United States Senate to represent the State of Iowa, concurrently with the 2016 U.S. presidential election, as well as other elections to the United States Senate in other states and elections to the United States House of Representatives and various state and local elections.
The 2022 United States Senate election in Iowa was held on November 8, 2022, to elect a member of the United States Senate to represent the State of Iowa. Incumbent Republican Senator Chuck Grassley defeated Democratic nominee Michael Franken to win re-election to an eighth term.