The 1820–21 United States House of Representatives elections were held on various dates in various states between July 3, 1820 and August 10, 1821. Each state set its own date for its elections to the House of Representatives before the first session of the 17th United States Congress convened on December 3, 1821. They coincided with President James Monroe winning reelection unopposed. In March 1820, seven House seats transferred from Massachusetts to Maine after the latter seceded from the former to become a separate state. The size of the House then increased to 187 seats after Missouri achieved statehood in 1821. The virtually nonpartisan Era of Good Feelings, a period of national political dominance by the Democratic-Republican Party, continued. Despite small gains, the Federalist Party remained relegated to limited state and local influence. Election summaries One seat was added during this Congress for the new State of Missouri Special elections There were special elections in 1820 and 1821 to the 16th United States Congress and 17th United States Congress. Special elections are sorted by date then district. 16th Congress |- ! | James Pleasants | | Democratic-Republican | 1817 | | Incumbent resigned December 14, 1819, when elected U.S. Senator.New member elected January 3, 1820.Democratic-Republican hold.Successor seated January 18, 1820.Successor later re-elected in the April 1821 election to the next term, see below. | nowrap | |- ! | John Condit | | Democratic-Republican | 1818 | | Incumbent resigned November 4, 1819, to become assistant collector of the Port of New York.New member elected February 2, 1820.Democratic-Republican hold.Successor seated February 16, 1820.Successor was not a candidate in the November 7, 1820, election for the next term, see below. | nowrap | |- ! | George F. Strother | | Democratic-Republican | 1817 | | Incumbent resigned February 10, 1820, to become as Receiver of Public Monies in St. Louis, Missouri.New member elected in August 1820.Democratic-Republican hold.Successor seated November 13, 1820.Successor later re-elected in the April 1821 election to the next term, see below. | nowrap | |- ! | William Woodbridge | | Unknown | 1819 | | Incumbent resigned August 9, 1820, due to family illness.New delegate elected sometime in 1820.Successor seated November 20, 1820.Successor later re-elected, see below. | nowrap | |- ! | James Pindall | | Federalist | 1817 | | Incumbent resigned July 6, 1820.New member elected sometime in 1820.Democratic-Republican gain.Successor seated November 13,