Boundary Atlas

ZIP code 57783: Spearfish, SD

ZIP code 57783 is in Spearfish (71% of residents), North Spearfish (15%) and Mountain Plains (2.0%), in Lawrence County (100%) and Butte County (0.2%), South Dakota. 12% of its residents live outside city limits. It is in South Dakota's at-large congressional district. Its state senate districts are State Senate District 31 (100%) and State Senate District 28 (0.2%); its state house districts are State House District 31 (100%) and State House District 28B (0.2%).

16,165residents (2020 Census)
213.2 sq miland area
3cities and towns
1congressional district
8voting precincts

See it on the mapAll of South Dakota

City and county

City or townShare of ZIP residents
Spearfish71%
North Spearfish15%
Mountain Plains2.0%

CountyShare of ZIP residents
Lawrence County100%
Butte County0.2%

Town or county subdivisionShare of ZIP residents
Spearfish city71%
North Lawrence UT28%
West Butte UT0.2%
South Lawrence UT<0.1%

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 31100%
State Senate District 280.2%

State house districtShare of ZIP residents
State House District 31100%
State House District 28B0.2%

Voting precincts

8 voting precincts overlap ZIP 57783. 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:57783")

ZIP 57783 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.