COUNTY · KS
Osage County, Kansas
Osage County is a county in Kansas with FIPS code 20139 and an estimated population of 15,824 (Census 2023), 32nd largest of 105 in the state.
County facts
- Name
- Osage County
- State
- Kansas
- Type
- county
- FIPS code
- 20139
- State FIPS
- 20
- Population (2023)
- 15,824
- Change since 2020
- +0.5%
- State rank
- 32 of 105
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Osage County?
Osage County, Kansas has the five-digit FIPS code 20139: 20 for the state and 139 for the county.
What state is Osage County in?
Osage County is in Kansas.
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.