The terms sound alike and both follow the census, so they are easy to confuse, but redistricting vs reapportionment describes two distinct steps. Reapportionment decides how many House seats each state gets. Redistricting decides where the district lines go inside each state. This guide explains each one, the order they happen in, and who is responsible. To see the result in your area, you can look up your congressional district by address or ZIP code.
What reapportionment is
Reapportionment is the reallocation of the 435 U.S. House seats among the 50 states after each decennial census. Because the total number of seats is fixed at 435, faster-growing states gain seats while slower-growing or shrinking states lose them. The Census Bureau reports the population counts, and the seats are divided using a formula called the method of equal proportions. Every state is guaranteed at least one seat.
What redistricting is
Redistricting is the redrawing of district boundaries within a state once it knows how many seats it has. The goal is to create districts of roughly equal population that comply with federal law. In most states the legislature draws the new congressional map, while a growing number of states use independent or bipartisan commissions. You can read a fuller walkthrough of how congressional redistricting works.
The order of events
The two steps happen in sequence after each census:
- First, the census counts the population.
- Next, reapportionment assigns each state its number of House seats.
- Finally, each state redistricts, drawing the boundaries for the number of seats it received.
A state that neither gains nor loses seats still redistricts, because population shifts inside the state mean the old lines no longer hold equal numbers of people.
Who does each one
Reapportionment is a national, formula-driven process handled through the Census Bureau and Congress; there is no map-drawing and no discretion once the counts are in. Redistricting is a state-level process with real choices about where lines go, which is why it is the step where gerrymandering can occur. If you want the background on that, see what gerrymandering is.
Why the difference matters
What the 2020 census changed
The 2020 census moved seats among the states through reapportionment. Texas gained two seats. Colorado, Florida, Montana, North Carolina, and Oregon each gained one. California, Illinois, Michigan, New York, Ohio, Pennsylvania, and West Virginia each lost one. The national total stayed at 435, so every seat one state gains, another loses. After the count, each of the 435 districts held about 761,000 people on average. States that gained or lost seats had the most redrawing to do, since their number of districts changed before any new lines could be set.
A worked example
Follow one state through both steps. After the 2020 census, Texas was assigned 38 House seats, up from 36. That assignment was reapportionment: it set the number. Texas then had to draw 38 district boundaries where 36 had been, fitting the two new seats into the map and adjusting the others for population. That line-drawing was redistricting. Reapportionment happened first and produced a single number. Redistricting came second and produced an actual map. A state whose seat count does not change skips the first effect but still redraws its lines to match new population counts.
Other terms people mix up
Two more words come up alongside these. Districting means drawing the district lines, the same activity as redistricting once the first maps exist. Gerrymandering is redistricting done to favor a party or group, by concentrating or splitting voters. Reapportionment never involves line-drawing at all; it only assigns each state its number of seats. Keeping them straight helps: reapportionment sets how many, redistricting sets where the lines fall, and gerrymandering describes lines drawn for advantage.
A quick way to keep them straight
If the two words still blur together, hold on to one contrast: reapportionment counts seats, and redistricting draws lines. Reapportionment is run by the federal government using census totals and changes only the number of seats each state holds. Redistricting is run by the states and changes the shape of the districts inside them. One produces a number, the other produces a map, and they happen in that order after every census. Once you can name which step is about counting and which is about drawing, the news coverage of each becomes easier to follow.
Reapportionment changes a state’s total voice in the House and in the Electoral College, since electoral votes depend on House seats. Redistricting changes which communities are grouped together and can shape who wins, even when the number of seats stays the same. Understanding both helps explain why a state can keep the same number of representatives yet still see very different districts from one decade to the next. To see your own district and representative, enter your address or ZIP on our home page or browse all 435 congressional districts.
Last updated August 3, 2026.
