The seats in the House were apportioned based on the 2010 United States census.

[1][2][3] The 2014 elections gave the Republicans control of the Senate and the House for the first time since the 109th Congress.

With 248 seats in the House of Representatives and 54 seats in the Senate, this Congress began with the largest Republican majority since the 71st Congress of 1929–1931.

As of 2025[update], this was the most recent Congress in which the Senate was controlled by the opposing party of the president for its entire session.

Section contents: Senate: Majority (R), Minority (D) • House: Majority (R), Minority (D) Senators are listed by state and then by Senate classes, In this Congress, Class 3 meant their term ended with this Congress, requiring re-election in 2016; Class 1 meant their term began in the last Congress, requiring re-election in 2018; and Class 2 meant their term began in this Congress, requiring re-election in 2020.