The 15th United States Congress was a meeting of the legislative branch of the United States federal government, consisting of the United States Senate and the United States House of Representatives. It met in the Old Brick Capitol in Washington, D.C. from March 4, 1817, to March 4, 1819, during the first two years of James Monroe's presidency. The apportionment of seats in the House of Representatives was based on the 1810 United States census. Both chambers had a Democratic-Republican majority.
The 1816–17 United States House of Representatives elections were held on various dates in various states between April 30, 1816 and August 14, 1817. Each state set its own date for its elections to the House of Representatives before the first session of the 15th United States Congress convened on December 1, 1817. The size of the House increased to 184 after Indiana and Mississippi achieved statehood.
The 1817 New York gubernatorial election was held in April/May 1817 to elect the Governor and Lieutenant Governor of New York.
The 1816–17 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 1816 and 1817, 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 1816 United States House of Representatives elections in New York were held from April 23 to 25, 1816, to elect 27 U.S. Representatives to represent the State of New York in the United States House of Representatives of the 15th United States Congress. At the same time, a vacancy was filled in the 14th United States Congress.
Pennsylvania elected its members October 8, 1816.
The 1817 Pennsylvania gubernatorial election occurred on October 14, 1817. Incumbent Democratic-Republican governor Simon Snyder was not a candidate for re-election. Simon's preferred successor, State Treasurer William Findlay, was nominated as the Democratic Republican candidate by a caucus of legislative leaders. Conversely, U.S. Representative Joseph Hiester was chosen as a candidate by the Democratic Republicans' first popular nominating convention; he additionally gained the endorsement of the declining Federalists.
North Carolina elected its members August 14, 1817.
Virginia elected its members in April 1817.
On March 12, 1815, a few days after the legal start of the 14th Congress, but long before the first meeting of that Congress, David Bard (DR), who'd been re-elected to the 9th district, died. A special election was held on October 10 to fill the vacancy left by his death.
A special election was held in Connecticut's at-large district in 1817 to fill two vacancies in the 15th Congress, both of which had occurred before the start of that Congress. The vacancies were left by the death of members-elect Sylvanus Backus (F) on February 15, 1817 and Charles Dennison (F) who declined the seat.
In the 1816 elections in Pennsylvania, David Scott (DR) won one of the two seats in the 10th district, but resigned before the 15th Congress began, having been appointed judge of the court of common pleas. A special election was held on October 14, 1817 to fill the resulting vacancy.
During the 15th Congress, there were two special elections in the 6th district of Pennsylvania, both held in the year 1818. The 6th district at that time was a plural district with two seats, both of which became vacant at different times in 1818. The first vacancy was caused by John Ross (DR) resigning on February 24, 1818 and the second was caused by Samuel D. Ingham (DR) resigning July 6.
On April 20, 1818, Jacob Spangler (DR) resigned from Congress, where he'd represented Pennsylvania's 4th district. A special election was held that year to fill the resulting vacancy.
The newly created state of Indiana elected its sole member of the U.S. House of Representatives in August 1816, in advance of statehood, to represent Indiana's at-large congressional district.
On November 3, 1817, John C. Calhoun (DR) of South Carolina's 6th district resigned upon being appointed Secretary of War. A special election was held for his replacement
A special election was held August 26, 1817 in Massachusetts's 1st congressional district to fill a vacancy left by the resignation of Representative-elect James Lloyd (F) before the beginning of the 15th Congress.
The 1817 Rhode Island gubernatorial election was held on April 16, 1817.
The 1817 New Hampshire gubernatorial election was held on March 11, 1817.