Boundary Atlas

ZIP code 57779: St. Onge, SD

ZIP code 57779 is in St. Onge (47% of residents), in Lawrence County (90%) and Butte County (9.9%), South Dakota. 53% 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 (90%) and State Senate District 28 (9.9%); its state house districts are State House District 31 (90%) and State House District 28B (9.9%).

364residents (2020 Census)
41.1 sq miland area
1cities and towns
1congressional district
3voting precincts

See it on the mapAll of South Dakota

City and county

City or townShare of ZIP residents
St. Onge47%

CountyShare of ZIP residents
Lawrence County90%
Butte County9.9%

Town or county subdivisionShare of ZIP residents
St. Onge township87%
West Butte UT9.9%
North Lawrence UT3.3%

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 3190%
State Senate District 289.9%

State house districtShare of ZIP residents
State House District 3190%
State House District 28B9.9%

Voting precincts

3 voting precincts overlap ZIP 57779. 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:57779")

ZIP 57779 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.