What is the purpose of the decennial census in relation to the House of Representatives?

The purpose of the decennial census in relation to the House of Representatives is to determine the number of representatives each state can elect. This is because the U.S. Constitution mandates that representation in the House is based on the population of each state. The census collects demographic data that helps in identifying population shifts and trends, which in turn influences congressional apportionment—the process of allocating the 435 seats in the House of Representatives among the states. States that experience population growth may gain additional representatives, while those with a decline may lose seats. This ensures that representation is reflective of the current population distribution, maintaining the principle of equal representation in the legislative process.