The United States Senate election of 1862 was an election during the American Civil War in which Republicans increased their control of the U.S. Senate. The Republican Party gained three seats, bringing their majority to 66% of the body. Also caucusing with them were Unionists and Unconditional Unionists. As many Southern states seceded in 1860 and 1861, and members left the Senate to join the Confederacy, or were expelled for supporting the rebellion, seats were declared vacant. To establish a quorum with fewer members, a lower total seat number was taken into account.