Boundary Atlas

ZIP code 59345: Custer County, MT

ZIP code 59345 is in Custer County (55%) and Powder River County (45%), Montana, outside any city or Census-designated place. It is in Montana's 2nd congressional district. Its state senate district is State Senate District 17; its state house district is State House District 34.

89residents (2020 Census)
543.0 sq miland area
0cities and towns
1congressional district
3voting precincts

See it on the mapAll of Montana

City and county

Outside any city or Census-designated place.


CountyShare of ZIP residents
Custer County55%
Powder River County45%

Town or county subdivisionShare of ZIP residents
South Custer CCD51%
East Powder River CCD44%
Shirley-Ismay CCD4.5%
Broadus CCD1.1%

Congressional district

Congressional districtShare of ZIP residents
Montana's 2nd congressional district (MT-02)100%

Members of Congress

OfficeMemberContact
U.S. Representative (MT-02)Troy Downing (R)202-225-3211
U.S. SenatorSteve Daines (R)202-224-2651 · contact form
U.S. SenatorTim Sheehy (R)202-224-2644

Members serving now (119th Congress, until January 3, 2027). Source: Members of Congress: the @unitedstates project, congress-legislators (CC0).

State legislative districts

State senate districtShare of ZIP residents
State Senate District 17100%

State house districtShare of ZIP residents
State House District 34100%

Voting precincts

3 voting precincts overlap ZIP 59345. 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:59345")

ZIP 59345 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.