Apportionment is the process of dividing the 435 memberships, or seats, in the U.S. House of Representatives among the 50 states.  Congress determines the method of apportionment. The U.S. Census Bureau is tasked with running the calculations based on Census results.

Number of Representatives
• The Constitution set the number of Representatives at 65 from 1787 until the first enumeration in 1790
• As specified in the Constitution after the 1790 Census, the number of Representatives was raised to 105
• Congress sets by law the number of Representatives

• The number of Representatives was set at 435 in 1911 and took effect when the 63rd Congress began its session in 1913

Resources

A New Portrait of America, First 2010 Census Results

Census 2010: Gains and Losses in Congress (Source: New York Times)

In The News

Democrats Spin Census Data as Both Parties See Gains and Losses
With census changes, GOP gains edge in races for Congress, president
South and West See Large Gains in Latest Census