The two houses of Congress are the House of Representatives and the Senate. They are both part of the legislative branch of the federal government and have equal but unique roles. The House of Representatives is made up of 435 elected members, divided among the 50 states in proportion to their total population. In addition, there are 6 non-voting members, representing the District of Columbia, the Commonwealth of Puerto Rico, and four other territories of the United States: American Samoa, Guam, the U.S. Virgin Islands, and the Commonwealth of Northern Mariana Islands. The presiding officer of the chamber is the Speaker of the House, elected by the Representatives. Members of the House are elected every two years and must be 25 years of age, a U.S. citizen for at least seven years, and a resident of the state (but not necessarily the district) they represent. The House has several powers assigned exclusively to it, including the power to initiate revenue bills, impeach federal officials, and elect the President in the case of an Electoral College tie.

The Senate, on the other hand, has 100 members and is the upper house of the United States Congress. It is called the upper house because it has fewer members than the House of Representatives and has powers not granted to the House, such as giving approval to appointments of Cabinet secretaries and federal judges. Every state has an equal voice in the Senate, and Senators are elected to six-year terms. Senators must be at least 30 years old, a U.S. citizen for at least nine years, and a resident of the state they represent. The Vice President of the United States serves as the President of the Senate, but can only vote in the case of a tie. The Senate also has several powers assigned exclusively to it, including the power to approve treaties and confirm presidential appointments.