COUNTY · OH
Miami County, Ohio
Miami County is a county in Ohio with FIPS code 39109 and an estimated population of 110,876 (Census 2023), 25th largest of 88 in the state.
County facts
- Name
- Miami County
- State
- Ohio
- Type
- county
- FIPS code
- 39109
- State FIPS
- 39
- Population (2023)
- 110,876
- Change since 2020
- +1.8%
- State rank
- 25 of 88
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Miami County?
Miami County, Ohio has the five-digit FIPS code 39109: 39 for the state and 109 for the county.
What state is Miami County in?
Miami County is in Ohio.
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.