Article 1, Section 2 of the U.S. Constitution dictates the number of congressmen for a state. As of 2015, there are 100 U.S. senators and 435 House representatives.
Congress, which includes the Senate and House of Representatives, is composed of 535 members. Each state is represented by two U.S. senators, regardless of population. Senators represent the state exclusively.
The House of Representatives is designed to represent the people rather than the states. The Constitution provides for proportional representation in the U.S. House of Representatives and the seats in the House are apportioned based on state population. The number of House members for each state is determined according to a statistical formula set out by federal law. Each state is then responsible for designing the shape of its districts, but it must do so in accordance with provisions of the Voting Rights Act of 1965, which seeks to protect racial minorities’ voting and representation rights.
Congress has capped the number of representatives at 435 since the Apportionment Act of 1911. Since that time, congressional districts have grown significantly. With those changes, along with population shifts, states either gain or lose seats based on population. As a result, each state’s congressional delegation is subject to change.