ZIP code 57421: Weston, SD
ZIP code 57421 is in Marshall County, South Dakota, outside any city or Census-designated place. 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.
See it on the mapAll of South Dakota
City and county
Outside any city or Census-designated place.
| County | Share of ZIP residents |
|---|---|
| Marshall County | 100% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| Weston township | 75% |
| Stena township | 25% |
| Miller township | land only |
Congressional district
| Congressional district | Share of ZIP residents |
|---|---|
| South Dakota's at-large congressional district (SD-AL) | 100% |
State legislative districts
| State senate district | Share of ZIP residents |
|---|---|
| State Senate District 1 | 100% |
| State house district | Share of ZIP residents |
|---|---|
| State House District 1 | 100% |
Voting precincts
3 voting precincts overlap ZIP 57421. 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:57421")
ZIP 57421 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.