The 2020 United States redistricting cycle is in progress following the completion of the 2020 United States census. In all fifty states, various bodies are re-drawing state legislative districts. States that are apportioned more than one seat in the United States House of Representatives are also drawing new districts for that legislative body.
The rules for redistricting vary from state to state, but all states draw new legislative and congressional maps either in the state legislature, in redistricting commissions, or through some combination of the state legislature and a redistricting commission. Though various laws and court decisions have put constraints on redistricting, many redistricting institutions continue to practice gerrymandering, which involves drawing new districts with the intention of giving a political advantage to specific groups. Political parties prepare for redistricting years in advance, and partisan control of redistricting institutions can provide a party with major advantages. Aside from the possibility of mid-decade redistricting, the districts drawn in the 2020 redistricting cycle will remain in effect until the next round of redistricting following the 2030 United States census.
United States House of Representatives
Reapportionment
Article One of the United States Constitution establishes the United States House of Representatives and apportions representatives to the states based on population, with reapportionment occurring every ten years. The decennial United States census determines the population of each state. Each of the fifty states is guaranteed at least one representative, and the Huntington–Hill method is used to assign the remaining 385 seats to states based on the population of each state. Congress has provided for reapportionment every ten years since the enactment of the Reapportionment Act of 1929. Since 1913, the U.S. House of Representatives has consisted of 435 members, a number set by statute, though the number of representatives temporarily increased in 1959. Reapportionment also affects presidential elections, as each state is guaranteed electoral votes equivalent to the number of representatives and senators representing the state.
Prior to the 2022 U.S. House elections, each state apportioned more than one representative will draw new congressional districts based on the reapportionment following the 2020 census. Based on the official counts of the 2020 census, California, Illinois, Michigan, New York, Ohio, Pennsylvania, and West Virginia will each lose one seat, while Colorado, Florida, Montana, North Carolina, and Oregon will each gain one seat, and Texas will gain two seats. Though California lost a seat for the first time in its history, the 2020 census continued a broader trend of Northeastern and Midwestern states losing seats and Western and Southern states gaining seats.
Congressional redistricting methods
Each U.S. representative represents one congressional district, which encompasses all or part of a single state. Every state with more than one congressional district must pass a new redistricting plan before the filing deadlines of the 2022 elections. In most states, the state legislature draws the new districts, but some states have established redistricting commissions. Arizona, California, Colorado, Idaho, Michigan, and Washington use independent commissions to draw House districts, while Hawaii and New Jersey use "politician commissions" to draw House districts. Alaska, Delaware, North Dakota, South Dakota, Vermont and Wyoming will continue to have only one representative in the House, and so will not have to draw new House districts.