
St Lucie County
- State:
- Florida
- County Seat:
- Fort Pierce
St. Lucie County's estimated 2025 population is 402,986 with a growth rate of 3.79% in the past year according to the most recent United States census data. St. Lucie County is the 20th largest county in Florida. The 2010 population was 278,290 and has seen a growth of 44.81% since that time.