Congressional redistricting is the process by which states redraw electoral district boundaries that determine representation in the US House of Representatives. The Constitution, federal law, and court rulings require districts to have roughly equal populations, be geographically contiguous, and avoid discrimination against racial or language minorities. For most of American history, redistricting has followed a predictable cycle, occurring every 10 years after the census.
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Every 10 years, states redraw congressional and legislative districts based on census data to ensure equal population. Legislatures usually control the process, though some states use independent commissions to curb partisan influence.
The term "gerrymandering" arose when Massachusetts Governor Elbridge Gerry approved a state senate map with a district so contorted it resembled a salamander. Critics dubbed it the "Gerry-mander," cementing the term for partisan map manipulation.
Cracking and packing are gerrymandering techniques. Cracking splits opposing voters across districts, diluting their power. Packing concentrates their votes into a few districts, wasting them in overwhelming majorities for one party.
This podcast explored whether courts can rein in partisan map-drawing, focusing on North Carolina's 2023 redistricting battle, the Moore v. Harper case, and the controversial "independent state legislature" theory.
Based on input from redistricting experts and political scientists, this resource identifies and ranks the most extreme congressional gerrymanders of the 2020s, examining how map design, cracking, and packing reduce competition and distort representation across states.
The National Conference of State Legislatures maintains a live tracker showing where mid-decade congressional redistricting is underway, detailing which states are pursuing new maps, the legislative and constitutional methods being used, and how courts are responding as the 2026 elections approach.
States have generally redrawn districts only once per decade following the census, with mid-decade redistricting occurring infrequently and usually prompted by court orders or unusual political circumstances.
Beginning in Texas, Republican-controlled legislatures in Missouri, Florida, Ohio, and North Carolina moved to redraw maps before 2030—an uncommon mid-decade effort aimed at securing additional congressional seats.
In response to Republican mid-decade redistricting efforts, Democratic leaders in California, New York, Illinois, and Maryland signaled plans to revisit their own congressional maps.
This podcast episode examines Baker v. Carr, a landmark redistricting ruling that Earl Warren called the most important of his tenure. The case was so divisive it triggered a justice's breakdown and permanently reshaped American democracy.
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