Article One of the Constitution of the United States establishes the legislative branch of the federal government, the United States Congress. Under Article One, Congress is a bicameral legislature consisting of the House of Representatives and the Senate. Article One grants Congress various enumerated powers and the ability to pass laws "necessary and proper" to carry out those powers. Article One also establishes the procedures for passing a bill and places various limits on the powers of Congress and the states from abusing their powers.

The United States Congress is the legislature of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washington, D.C. Senators and representatives are chosen through direct election, though vacancies in the Senate may be filled by a governor's appointment. Congress has 535 voting members: 100 senators and 435 representatives. The U.S. vice president has a vote in the Senate only when senators are evenly divided. The House of Representatives has six non-voting members.