Ottawa
- County:
- Putnam County
- County Seat:
- Yes
- Area (mi²):
- 4.547
- State:
- Ohio
Ottawa is a village located in Putnam County, Ohio. Ottawa has a 2026 population of 4,422. It is also the county seat of Putnam County. Ottawa is currently declining at a rate of -0.23% annually and its population has decreased by -0.9% since the most recent census, which recorded a population of 4,462 in 2020.