
Allen County
- State:
- Indiana
- County Seat:
- Fort Wayne
Allen County's estimated 2025 population is 400,347 with a growth rate of 0.73% in the past year according to the most recent United States census data. Allen County is the 3rd largest county in Indiana. The 2010 population was 355,956 and has seen a growth of 12.47% since that time.