Boundary Atlas

Iowa: cities, counties, ZIP codes and districts

Iowa has 4 congressional districts, 50 state senate districts and 100 state house districts under the maps in force for November 3, 2026, plus 1,660 voting precincts, 99 counties, 1,026 cities, towns and Census-designated places, and 970 ZIP codes.

Cities and towns

Largest first. Each page lists the city's county, districts and ZIP codes.

Congressional districts (2026)

DistrictShort2020 population
Iowa's 1st congressional districtIA-01797,584
Iowa's 2nd congressional districtIA-02797,589
Iowa's 3rd congressional districtIA-03797,551
Iowa's 4th congressional districtIA-04797,645

ZIP codes in Iowa

Each page lists the ZIP's congressional and legislative districts, with population shares where it's split.

Get this in your AI agent

Your agent can list, look up and map every district and precinct in Iowa. Add https://atlas-production-d344.up.railway.app/mcp to Claude, ChatGPT, Cursor or Codex (free, no key; how), then:

list_geographies(country="US", level="congressional_district", region="IA")