| City | Rank | 2026 Pop. ↓ | 2020 Pop. | Annual Change | Density (/mi²) | Area (mi²) | Type |
|---|---|---|---|---|---|---|---|
| Port Clinton | 1 | 5,851 | 6,013 | -0.41% | 2,746 | 2 | City |
| Oak Harbor | 2 | 2,773 | 2,820 | -0.25% | 1,747 | 2 | Village |
| Genoa | 3 | 2,157 | 2,229 | -0.46% | 1,080 | 2 | Village |
| Elmore | 4 | 1,363 | 1,406 | -0.51% | 1,474 | 1 | Village |
| Marblehead | 5 | 825 | 848 | -0.48% | 260 | 3 | Village |
| Rocky Ridge | 6 | 302 | 310 | -0.33% | 301 | 1 | Village |
| Clay Center | 7 | 244 | 260 | -1.21% | 241 | 1 | Village |
| Put-in-Bay | 8 | 151 | 156 | -0.66% | 344 | 0 | Village |
Port Clinton is the largest city in Ottawa County, with a population of 5,851.
Put-in-Bay is the smallest city in Ottawa County, with a population of 151.
There are 8 cities in Ottawa County, Ohio.