What is redistricting?
Redistricting redraws district boundaries to reflect population changes. States usually redraw congressional districts after the census every ten years so districts within each state have equal populations.
The lines decide which voters elect each U.S. House member. Your district can change even if you never move. U.S. senators represent whole states, so congressional redistricting does not change their boundaries.
Apportionment counts seats. Redistricting draws lines.
Apportionment divides the 435 voting House seats among the states using census population counts. Each state gets at least one seat. A state can gain seats, lose seats, or keep the same number.
Redistricting draws the boundaries for those seats within each state. Even a state that keeps the same seat count may need new lines because people moved within it. A state with one House seat has one statewide, at-large district, so it has no internal congressional lines to redraw.
The Census Bureau’s congressional district guide explains how seats and district boundaries fit together.
How do states redraw congressional districts?
- The census counts people. Every ten years, the Census Bureau counts the population. Its Redistricting Data Program supplies states with population totals for small areas, including census blocks.
- Mapmakers draft districts. They combine those areas into districts for the state’s allotted House seats. Congressional districts within a state must have populations as equal as practicable, not equal land areas.
- The state reviews and adopts a map. State rules determine public hearings, map submissions, approval, and deadlines. Residents can check the state’s redistricting website for ways to comment.
- Election officials use the approved boundaries. Legal challenges can lead courts to require changes or adopt a replacement map. Election officials identify which map applies to each election.
Who draws the lines, and what rules apply?
The Census Bureau provides data, not the final district map. In many states, the legislature draws the map, often subject to the governor’s veto. Other states use commissions. Some commissions adopt maps, while others advise lawmakers or act if lawmakers cannot agree.
The Brennan Center’s redistricting explainer describes these roles. States must follow federal constitutional requirements and the Voting Rights Act, including protections against racial discrimination.
State rules may also require connected districts, compact shapes, or respect for county boundaries and communities with shared interests. The 50-state redistricting guide explains how those rules differ.
Is redistricting the same as gerrymandering?
No. Redistricting is the process of redrawing boundaries. Gerrymandering uses those boundaries to give a political party or group an unfair advantage. Either party can do it when it controls the map.
Read the gerrymandering guide to see how packing voters together and cracking them apart can change election results.
Your district can change. Follow the votes.
Maps can change between censuses through court orders or mid-decade redistricting, where the law allows it. A new election map does not immediately replace your current representative. Check your state or local election office for the district on your next ballot.
The district guide shows how to confirm your current House district with the official House lookup. Use your home street address because a ZIP code can cross district lines.
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