ZIP code 57645: Morristown, SD
ZIP code 57645 is in Morristown (27% of residents), in Corson County (58%), Grant County (23%) and Sioux County (19%), South Dakota. 73% of its residents live outside city limits. It is in South Dakota's at-large congressional district (58%) and North Dakota's at-large congressional district (42%). Its state senate districts are State Senate District 28 (58%) and State Senate District 31 (42%); its state house districts are State House District 28A (58%) and State House District 31 (42%).
See it on the mapAll of South Dakota
City and county
| City or town | Share of ZIP residents |
|---|---|
| Morristown | 27% |
| County | Share of ZIP residents |
|---|---|
| Corson County | 58% |
| Grant County | 23% |
| Sioux County | 19% |
| Town or county subdivision | Share of ZIP residents |
|---|---|
| Morristown town | 27% |
| West Corson UT | 20% |
| Southwest Sioux UT | 19% |
| East Grant UT | 16% |
| Custer township | 11% |
| Howe township | 7.0% |
| Pretty Rock township | land only |
| Prairie View township | land only |
Congressional districts
| Congressional district | Share of ZIP residents |
|---|---|
| South Dakota's at-large congressional district (SD-AL) | 58% |
| North Dakota's at-large congressional district (ND-AL) | 42% |
This ZIP is split between districts. A mailing address in it could be in either; the map or locate_point gives the district for an exact address.
Elected officials
| Office | Member | Contact | Share of residents |
|---|---|---|---|
| U.S. Representative (SD-AL) | Dusty Johnson (R) | 202-225-2801 | 58% |
| U.S. Representative (ND-AL) | Julie Fedorchak (R) | 202-225-2611 | 42% |
| U.S. Senator | John Thune (R) | 202-224-2321 · contact form | statewide |
| U.S. Senator | Mike Rounds (R) | 202-224-5842 · contact form | statewide |
| State Senator (State Senate District 28) | Sam Marty (R) | 58% | |
| State Senator (State Senate District 31) | Don Schaible (R) | 42% | |
| State Representative (State House District 28A) | Jana Hunt (R) | 58% | |
| State Representative (State House District 31) | Dawson Holle (R) | 42% | |
| State Representative (State House District 31) | Karen Rohr (R) | 42% |
Officials serving now (members of Congress until January 3, 2027). Sources: State legislators: Open States (public domain); Members of Congress: the @unitedstates project, congress-legislators (CC0).
Local government
- Morristown laws: search for the Morristown, South Dakota code of ordinances
- Corson County website: http://corson.sdcounties.org
- Corson County laws: search for the Corson County, South Dakota code of ordinances
- Grant County website: http://grantcountynd.com
- Grant County laws: search for the Grant County, South Dakota code of ordinances
State legislative districts
| State senate district | Share of ZIP residents |
|---|---|
| State Senate District 28 | 58% |
| State Senate District 31 | 42% |
| State house district | Share of ZIP residents |
|---|---|
| State House District 28A | 58% |
| State House District 31 | 42% |
Voting precincts
5 voting precincts overlap ZIP 57645. It also crosses into ND. 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:57645")
ZIP 57645 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.