Apportionment is the decennial constitutional process of allocating the 435 House of Representatives seats among the 50 states based on population as measured by the Census. Each state gets at least one representative, regardless of population—Wyoming has roughly 580,000 people but holds one House seat; California has 39 million and holds 52 seats. The remaining seats are distributed to states with largest populations.
Congress uses the Huntington-Hill method (adopted in 1941) to calculate apportionment. The method compares each state's "priority value"—a mathematical calculation of population relative to current seats—to determine whether each additional seat should go. This method generally allocates seats proportional to population while ensuring every state gets at least one, though no method perfectly reflects population in a chamber with only 435 seats.
Apportionment results cascade through the political system. States that gain seats gain House members and Electoral College votes; states that lose seats lose influence. In 2020, Texas gained two seats while California, Illinois, Michigan, New York, Ohio, Pennsylvania, and West Virginia each lost one. Texas moved from 36 to 38 seats; California fell from 53 to 52. These shifts often reflect regional migration: people moving from older industrial states to Sun Belt and Rocky Mountain states.
Apportionment determines which states gain or lose political power in Congress and the Electoral College for the next decade. Population migration creates winners and losers—and the political map literally redraws itself every 10 years.
People often confuse apportionment with redistricting. Apportionment determines how many House seats each state gets (a number); redistricting redraws district boundaries within states (geography). Both happen after the Census, but they're separate processes.
Apportionment determines which states gain or lose political power in Congress and the Electoral College for the next decade. Population migration creates winners and losers—and the political map literally redraws itself every 10 years.
People often confuse apportionment with redistricting. Apportionment determines how many House seats each state gets (a number); redistricting redraws district boundaries within states (geography). Both happen after the Census, but they're separate processes.