
Hamilton County
- State:
- Indiana
- County Seat:
- Noblesville
Hamilton County's estimated 2025 population is 384,009 with a growth rate of 1.64% in the past year according to the most recent United States census data. Hamilton County is the 4th largest county in Indiana. The 2010 population was 276,499 and has seen a growth of 38.88% since that time.