The House of Representatives is one of the two houses of the Congress of the United States, which possesses the legislative power of the federal government. Unlike the Senate, the House of Representatives uses a system of proportional representation to determine its composition; seats are allocated to each state on the basis of that state’s population.
The state legislature then divides the state into Congressional districts, each of which elects one representative every two years. Today, each Congressional district must contain roughly the same number of people in order to ensure that one person’s vote in a Congressional election is worth as much as another’s. The original House of Representatives started with 60 members. The number of representatives grew over time but was fixed at 435 in 1929. – The United States Constitution, What It Says, What It Means, A Hip Pocket Guide