Congressional District Size

Updated September 14, 2021 | Infoplease Staff
Source: U.S. Census Bureau

Apportionment is the process of dividing the 435 seats in the House of Representatives among the 50 states. The number of seats, or representatives, each state is entitled to is apportioned according to the new census figures that are compiled every 10 years. States with larger populations have more representatives than states with smaller populations. Each state must have at least one representative.

Once the number of seats is assigned to each state, it is up to the individual state legislatures to redraw new congressional districts. Each representative is elected by voters from a congressional district within their state.

The population figure used to calculate the apportionment of House seats is based on the total resident population of the United States, including citizens and noncitizens, plus U.S. military personnel and federal civilian employees and their dependents living overseas. It excludes the populations of the District of Columbia, Puerto Rico, and other U.S. territories that do not have voting seats in the House of Representatives. The Census 2000 apportionment population was 281,424,177.

Congressional District Size

The number of representatives in the U.S. House of Representatives has remained constant at 435 since 1911, except for a temporary increase to 437 at the time of admission of Alaska and Hawaii as states in 1959. However, the apportionment based on the 1960 census, which took effect for the election of 1962, reverted to 435 seats.

The average size of a congressional district based on the Census 2000 apportionment population will be 646,952, more than triple the average district size of 193,167 based on the 1900 census apportionment, and about 74,486 more than the average size of 572,466 based on the 1990 census.

Congressional Seats Gained/Lost in the 108th Congress1

Seats gained
+ 2 seats +1 seat
Arizona (8) California (53)
Florida (25) Colorado (7)
Georgia (13) Nevada (3)
Texas (32) North Carolina (13)
Seats lost
–1 seat –2 seats
Connecticut (5) New York (29)
Illinois (19) Pennsylvania (19)
Indiana (9)  
Michigan (15)  
Mississippi (4)  
Ohio (18)  
Oklahoma (5)  
Wisconsin (8)  
NOTE: The number of representatives based on Census 2000 is given in parentheses after each state.
1. Based on Census 2000.
Source: U.S. Census Bureau, Census 2000. Web:



Major Congressional Bills Passed in 2005 U.S. Government Senate Salaries since 1789



Sources +