COUNTY · FL
St. Johns County, Florida
St. Johns County is a county in Florida with FIPS code 12109 and an estimated population of 320,110 (Census 2023), 22nd largest of 67 in the state.
County facts
- Name
- St. Johns County
- State
- Florida
- Type
- county
- FIPS code
- 12109
- State FIPS
- 12
- Population (2023)
- 320,110
- Change since 2020
- +15.5%
- State rank
- 22 of 67
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for St. Johns County?
St. Johns County, Florida has the five-digit FIPS code 12109: 12 for the state and 109 for the county.
What state is St. Johns County in?
St. Johns County is in Florida.
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.