Boundary Atlas

ZIP code 57445: Groton, SD

ZIP code 57445 is in Groton (71% of residents), in Brown County, South Dakota. 29% of its residents live outside city limits. It is in South Dakota's at-large congressional district. Its state senate district is State Senate District 1; its state house district is State House District 1.

1,951residents (2020 Census)
253.9 sq miland area
1cities and towns
1congressional district
4voting precincts

See it on the mapAll of South Dakota

City and county

City or townShare of ZIP residents
Groton71%

CountyShare of ZIP residents
Brown County100%

Town or county subdivisionShare of ZIP residents
Groton city71%
Groton township6.0%
Henry township5.2%
Putney township4.7%
East Hanson township3.5%
Riverside township2.8%
West Hanson township2.8%
Gem township2.5%
Bates township0.9%
Claremont township0.9%
Cambria townshipland only

Congressional district

Congressional districtShare of ZIP residents
South Dakota's at-large congressional district (SD-AL)100%

State legislative districts

State senate districtShare of ZIP residents
State Senate District 1100%

State house districtShare of ZIP residents
State House District 1100%

Voting precincts

4 voting precincts overlap ZIP 57445. Map them, with each precinct's share of the ZIP's residents.

Get this in your AI agent

Your agent can get these cities, counties, districts and precincts with their shares, and their GeoJSON boundaries, from Boundary Atlas. Add https://atlas-production-d344.up.railway.app/mcp to Claude, ChatGPT, Cursor or Codex (free, no key; how), then:

related_geographies(id="us:zcta:57445")

ZIP 57445 here is the Census Bureau's ZIP Code Tabulation Area, which approximates the USPS ZIP Code; PO-box-only ZIPs have none. Districts are the maps in force for the November 3, 2026 election.