
Ottawa County
- State:
- Ohio
- County Seat:
- Port Clinton
Ottawa County's estimated 2025 population is 39,473 with a growth rate of -0.42% in the past year according to the most recent United States census data. Ottawa County is the 62nd largest county in Ohio. The 2010 population was 41,359 and has seen a growth of -4.56% since that time.