This is a list of the several United States Congresses, since their beginning in 1789, including their beginnings, endings, and the dates of their individual sessions. Each elected bicameral Congress (of the two chambers of the Senate and the House of Representatives) lasts for two years and begins on January 3 of odd-numbered years.
Before the Twentieth Amendment to the United States Constitution (ratified January 23, 1933), which moved and fixed new Congressional dates, on which an American Congress began and ended, designated from the original provisions of the Constitution of 1787, was previously either March 3 or March 4, (in tandem then with dates of presidential inaugurations every fourth year which were moved by the same constitutional amendment to January 20).