Congressional elections are held in the United States to select members of the U.S. Congress, which consists of two chambers: the House of Representatives and the Senate. These elections occur every two years, with all 435 members of the House and about one-third of the 100 Senate seats up for election. Candidates typically represent political parties, such as the Democratic Party or the Republican Party, and they campaign to gain support from voters in their districts or states. The elections are crucial for determining the legislative agenda and the balance of power in Congress.