COUNTY · MO
St. Clair County, Missouri
St. Clair County is a county in Missouri with FIPS code 29185 and an estimated population of 9,752 (Census 2023), 88th largest of 115 in the state.
County facts
- Name
- St. Clair County
- State
- Missouri
- Type
- county
- FIPS code
- 29185
- State FIPS
- 29
- Population (2023)
- 9,752
- Change since 2020
- +4.3%
- State rank
- 88 of 115
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for St. Clair County?
St. Clair County, Missouri has the five-digit FIPS code 29185: 29 for the state and 185 for the county.
What state is St. Clair County in?
St. Clair County is in Missouri.
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.