Apportionment is the process of dividing the 435 memberships, or seats, in the House of Representatives among the 50 states based on the population figures collected during the decennial census.
State or Region
1960 Census 1
1920 Census 2
1910 Census 3
X Not applicable. Represents date prior to becoming a state.
Note 1: Apportionment is the process of dividing up the number of representatives (or seats) in the U.S. House of Representatives among the 50 states. The District of Columbia and Puerto Rico are not included.
Note 2: The values for the "United States" that are shown in the "Change in Seats" row indicate the total number of seats that were reassigned that decade (except for the 1910 value, which indicates the number of seats added to the U.S. House of Representatives since 1900).
1 In 1959, Alaska and Hawaii became states and were each granted a seat—temporarily increasing the size of the House to 437. The size of the House for the 1960 apportionment reverted back to the fixed size of 435 seats. 2 In 1912, Arizona and New Mexico became states and each were granted a seat—temporarily increasing the size of the House to 435. In 1920, the Census Bureau did transmit apportionment counts to Congress, but Congress did not reapportion. The size of the House during the next apportionment, in 1930, was fixed at 435. 3 In 1900, there were 386 seats in the House. In 1907, Oklahoma became a state and was granted 5 seats—temporarily increasing the size of the House to 391. The size of the House during the next apportionment, in 1910, was increased to 433.