
St. Johns County
- State:
- Florida
- County Seat:
- Saint Augustine
St. Johns County's estimated 2025 population is 346,186 with a growth rate of 3.91% in the past year according to the most recent United States census data. St. Johns County is the 21st largest county in Florida. The 2010 population was 191,268 and has seen a growth of 81% since that time.