The 1860–61 United States House of Representatives elections were held on various dates in various states between August 6, 1860 and October 24, 1861, before or after the first session of the 37th United States Congress convened on July 4, 1861. The number of House seats initially increased to 239 when California was apportioned an extra one, but these elections were affected by the outbreak of the American Civil War and resulted in over 56 vacancies. In November 1860, Republican Abraham Lincoln won the Presidency. Though Republicans lost seats, the party won a House majority anyway as seven slave states reacted to Lincoln's election by seceding before the Presidential inauguration. These seceding states formed the Confederacy in February 1861 while withdrawing many Representatives and Senators from Congress, almost all Democrats. As both sides in the impending American Civil War initially mobilized troops, another four slave states seceded by May 1861 in response to Lincoln's policy of using Federal force to defend Federal property and to coerce the seven initially seceding states. The four remaining slave states did not secede, electing and returning Representatives normally. Unionist regions of three seceding states returned ten Representatives: five from western Virginia, three from eastern Tennessee, and two from southern Louisiana. Except for a tiny minority of outspoken Democrats, all Representatives supported the Union. Representatives opposing Democrats but unwilling to identify as Republican, particularly from slave states and including some remaining nativist American Party members, coalesced as the Unionist Party. In coalition with the Unionists, Republicans commanded over a two-thirds House supermajority. Election summaries California was apportioned one additional seat for the 37th Congress, increasing the total seats to 239. Representatives from seceding states overwhelmingly were Democrats. Withdrawal of these Representatives boosted Republican House control. Some seceding states held Federal elections, but seceded before the elected Representatives served. Other seceding states held no Federal elections. Special elections There were special elections in 1860–61 during the 36th United States Congress and 37th United States Congress. 36th Congress |- ! | Francis P. Blair Jr. | | Republican | 18561858 1860 | | Incumbent resigned June 25, 1860.New member elected October 3, 1860.Democratic gain.Winner lost election to the next term, see below. | nowrap | |- ! | John Schwartz | | Anti-Lecompton Democratic | 1858 | | Incumbent died June 20, 1860.New member elected October 9, 1860.Democratic hold.Winner was not a candidate for election to the