As of 2015, the two senators with the largest constituency in the U.S. Senate are Sen. Dianne Feinstein and Sen, Barbara Boxer. Both are Democrats from California. A senator's constituency size consists of the entire official population of the state that he or she represents.
California's constituency, at almost 39 million people, is by far the largest represented in the U.S. Senate. The second largest constituency is made up of the people of Texas, at approximately 28 million people, while the constituencies of Florida and New York are a distant third and fourth.
Constituency size has no affect on representation in the U.S. Senate. Each state has two senators and two votes when it comes to crafting important legislation, regardless of the size of its constituency. The two senators from California wield no more voting power than the two senators from Wyoming, the least populous state. However, in Congress's other legislative chamber, the House of Representatives, a state's constituency size directly determines the number of representatives that it sends to Congress. This setup is a result of what is called the "Great Compromise" reached by the original states during the Constitutional Convention, resulting in a bicameral legislature in which one chamber gave equal representation to every state no matter the size, and the other chamber functioned under representation according to population or constituency size.