COUNTY · MT
Custer County, Montana
Custer County is a county in Montana with FIPS code 30017 and an estimated population of 11,985 (Census 2023), 17th largest of 56 in the state.
County facts
- Name
- Custer County
- State
- Montana
- Type
- county
- FIPS code
- 30017
- State FIPS
- 30
- Population (2023)
- 11,985
- Change since 2020
- +1.0%
- State rank
- 17 of 56
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Custer County?
Custer County, Montana has the five-digit FIPS code 30017: 30 for the state and 017 for the county.
What state is Custer County in?
Custer County is in Montana.
How do I know if an address is in this county?
Use the address lookup. ZIP codes and city names can cross county lines, so an address is the reliable check.
Sources: U.S. Census Bureau geographic reference files; Census Bureau Population Estimates, Vintage 2023. Last reviewed 2026-10-27.