The 1870 United States general election occurred in the middle of Republican President Ulysses S. Grant's first term, during the Third Party System. Members of the 42nd United States Congress were chosen in this election. The Republican Party maintained a majority in both houses of Congress, although Democrats picked up several seats in both chambers.
In the House, Democrats won major gains, but Republicans retained a solid majority.
In the Senate, Democrats won moderate gains, but Republicans retained a commanding majority.