The United States Congress is the legislative branch of the federal government of the United States. It is a bicameral legislature, including a lower body, the U.S. House of Representatives, and an upper body, the U.S. Senate. They both meet in the United States Capitol in Washington, D.C.
Members of Congress are chosen through direct election, though vacancies in the Senate may be filled by a governor's appointment. Congress has a total of 535 voting members: 100 senators and 435 representatives. The House of Representatives also has 6 additional non-voting members. The vice president of the United States, as president of the Senate, has a vote in the Senate only when there is a tie.
Congresses convene for two-year terms (a Congress), commencing every other January. Each Congress is usually split into two sessions, one for each year. Elections are held every even-numbered year on Election Day. The members of the House of Representatives are elected for the two-year term of a Congress. The Reapportionment Act of 1929 established that there be 435 representatives, and the Uniform Congressional District Act requires that they be elected from single-member constituencies or districts. It is also required that the congressional districts be apportioned among states by population every ten years using the U.S. census results, provided that each state has at least one congressional representative. Each senator is elected at-large in their state for a six-year term, with terms staggered, so every two years approximately one-third of the Senate is up for election. Each state, regardless of population or size, has two senators, so currently, there are 100 senators for the 50 states.
Article One of the Constitution requires that members of Congress be at least 25 years old for the House and at least 30 years old for the Senate, be a U.S. citizen for seven years for the House and nine years for the Senate, and be an inhabitant of the state which they represent. Members in both chambers may stand for re-election an unlimited number of times.
Congress was created by the Constitution's First Article and first met in 1789, replacing the Congress of the Confederation in its legislative function. Although not legally mandated, in practice members of Congress since the late 19th century are typically affiliated with one of the two major parties, the Democratic Party or the Republican Party, and only rarely with a third party or independents affiliated with no party. Members can also switch parties at any time, though this is uncommon.
Article One of the United States Constitution states, "All legislative Powers herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and House of Representatives." The House and Senate are equal partners in the legislative process – legislation cannot be enacted without the consent of both chambers. The Constitution grants each chamber some unique powers. The Senate ratifies treaties and approves presidential appointments while the House initiates revenue-raising bills.
The House initiates and decides impeachment while the Senate votes on conviction and removal of office for impeachment cases. A two-thirds vote of the Senate is required before an impeached person can be removed from office.
The term Congress can also refer to a particular meeting of the legislature. A Congress covers two years; the current one, the 119th Congress, began on January 3, 2025, and will end on January 3, 2027. Since the adoption of the Twentieth Amendment to the United States Constitution, the Congress has started and ended at noon on the third day of January of every odd-numbered year. Members of the Senate are referred to as senators, while members of the House of Representatives are commonly referred to as representatives, congressmen, or congresswomen.
Congress provides both local representation of congressional districts by representatives and representation of states at-large by senators.
Scholar and representative Lee H. Hamilton asserted that the "historic mission of Congress has been to maintain freedom" and insisted it was a "driving force in American government" and a "remarkably resilient institution". Congress is the "heart and soul of our democracy", according to this view, even though legislators rarely achieve the prestige or name recognition of presidents or Supreme Court justices; one wrote that "legislators remain ghosts in America's historical imagination." One analyst argues that it is not a solely reactive institution but has played an active role in shaping government policy and is extraordinarily sensitive to public pressure. Several academics described Congress:
Congress reflects us in all our strengths and all our weaknesses. It reflects our regional idiosyncrasies, our ethnic, religious, and racial diversity, our multitude of professions, and our shadings of opinion on everything from the value of war to the war over values. Congress is the government's most representative body ... Congress is essentially charged with reconciling our many points of view on the great public policy issues of the day.
Congress is constantly changing and is constantly in flux. In recent times, the American South and West have gained House seats according to demographic changes recorded by the census and includes more women and minorities. Most incumbents seek re-election, and their historical likelihood of winning subsequent elections exceeds 90 percent.
While power balances among the different parts of government continue to change, the internal structure of Congress is important to understand along with its interactions with so-called intermediary institutions such as political parties, civic associations, interest groups, and the mass media.
The historical records of the House of Representatives and the Senate are maintained by the Center for Legislative Archives, which is a part of the National Archives and Records Administration.
Congress holds legislative authority over the District of Columbia, as the current seat of the federal government. Despite the devolution of certain roles to municipal government, under the Home Rule Act, Congress has the power to 'review and disapprove' local laws before they take effect.
The First Continental Congress was a gathering of representatives from twelve of the Thirteen Colonies. On July 4, 1776, the Second Continental Congress adopted the Declaration of Independence, referring to the new nation as the "United States of America". The Articles of Confederation in 1781 created the Congress of the Confederation, a unicameral body with equal representation among the states in which each state had a veto over most decisions. Congress had executive but not legislative authority, and the federal judiciary was confined to admiralty and lacked authority to collect taxes, regulate commerce, or enforce laws.
Government powerlessness led to the Convention of 1787 which proposed a revised constitution with a two-chamber or bicameral Congress. Smaller states argued for equal representation for each state. The two-chamber structure had functioned well in state governments. A compromise plan, the Connecticut Compromise, was adopted with representatives chosen by population (benefiting larger states) and exactly two senators chosen by state governments (benefiting smaller states).
The ratified constitution created a federal structure with two overlapping power centers so that each citizen as an individual is subject to the powers of state government and national government. To protect against abuse of power, each branch of government – executive, legislative, and judicial – had a separate sphere of authority and could check other branches according to the principle of the separation of powers. Furthermore, there were checks and balances within the legislature since there were two separate chambers. The new government became active in 1789.