Redistricting definition
Redistricting redraws election district boundaries to reflect population changes. It's a state process, but is governed by federal law.
Redistricting is the process of redrawing the boundaries of an electoral district to reflect changes in its population. The process determines how communities are grouped for political representation, shaping who is elected to Congress, state legislatures, and local governing bodies.
Redistricting is a state process, but is governed by federal law. The US Constitution, as interpreted by the Supreme Court, requires that each of a state’s congressional districts have nearly equal populations, and the Voting Rights Act of 1965 prohibits maps that weaken the voting power of racial or language minority groups.
A 2026 Supreme Court ruling, Louisiana v. Callais, raised the bar for proving those claims. A map now violates the law only when evidence strongly suggests a state drew its districts to intentionally limit voting opportunity based on race. Some states have begun redrawing their maps in response.
Within those boundaries, states have broad authority to set their own redistricting practices, including when new maps are drawn.
How often does redistricting occur?
Redistricting typically happens every 10 years, after each census. The census is the once-a-decade population count run by the US Census Bureau. When the count shows that the populations in some areas grew while others shrank, district lines must shift so each district still holds roughly the same number of people.
Neither the Constitution nor federal law bars a state from redrawing its districts mid-decade.
Who is responsible for redistricting?
The authority for drawing district lines depends on the state. In most states, the legislature controls the process, often subject to the governor's approval, while other states use independent or advisory commissions to draw the maps. States with a single House seat, such as Wyoming, Vermont, and Alaska, do not draw congressional district lines but still redraw districts for state legislative seats.
What is the difference between redistricting and gerrymandering?
Gerrymandering is the manipulation of district boundaries during redistricting to favor a political party, group, or incumbent. It often produces oddly-shaped districts.
There are a range to manipulate voting districts: “packing” concentrates voters of one group into a single/a few districts, while “cracking” spreads them across many districts so they can’t form a majority anywhere.
Keep exploring
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- Reapportionment and redistricting after the 2020 census: Explained - Texas gained two congressional seats while seven states lost a seat following the 2020 census. In all, seven seats shifted between 13 states.
- More voters are registering outside the two party system - We mapped voter registration in every state that tracks party affiliation. In three out of four counties, the share of voters registered outside the two major parties grew over the past decade.
- Tracking 2024 election contributions and spending - A majority of funding for the 2024 election — over 65%, or nearly $5.6 billion — comes from political action committees, also known as PACs.
