1860–61 United States House of Representatives elections
The 1860–61 United States House of Representatives elections took place between August 6, 1860, and October 24, 1861 to elect 180 representatives and seven non-voting delegates to the 37th United States Congress. The Republican Party lost seats but gained a majority in the chamber following the withdrawal of the representatives from the Confederate States of America.
Source: Wikipedia — 1860–61 United States House of Representatives elections (CC BY-SA 4.0)