The United States Congress is the bicameral legislature of the federal government of the United States of America, consisting of the Senate and the House of Representatives. Both senators and representatives are chosen through direct election.

Each of the 435 members of the House of Representatives represents a district and serves a two-year term. House seats are apportioned among the states by population. The 100 Senators serve staggered six-year terms. Each state has two senators, regardless of population. Every two years, approximately one-third of the Senate is elected at a time. Re-election rates for incumbents often exceed 90%.

Article I of the Constitution vests all legislative power in Congress. The House and Senate are equal partners in the legislative process (legislation cannot be enacted without the consent of both chambers); however, the Constitution grants each chamber some unique powers. The Senate is uniquely empowered to ratify treaties and to approve top presidential appointments. Revenue-raising bills must originate in the House of Representatives, which also has the sole power of impeachment, while the Senate has the sole power to try impeachment cases.

The Congress meets in the U.S. Capitol in Washington, D.C.

The term Congress is also used to refer to a particular meeting of the national legislature, reckoned according to the terms of representatives. Therefore, a "Congress" covers two years. The current 111th Congress convened on January 6, 2009.