The history of the United States Congress refers to the chronological record of the United States Congress including legislative sessions. The Constitution defines the Senate as having two senators for each state in the Union. The size of the House of Representatives is based on the number of states and their populations. The numerical size of the House is set by law, not by the Constitution. The House grew in size as states were admitted throughout the 19th century, and as the nation grew in population. Since the Constitution allows for one representative for as few as 30,000 citizens, Congress passed new, higher limits for the House, which grew in size until a law passed in 1911, based on the National Census of 1910, established the present upper limit of 435 members of the House. Since