Towns
| State | City/Town | Town Title |
|---|---|---|
| Ohio | Ontario | Ontario, OH |
| Ohio | Orangeville | Orangeville, OH |
| Ohio | Oregon | Oregon, OH |
| Ohio | Oregonia | Oregonia, OH |
| Ohio | Orient | Orient, OH |
| Ohio | Orrville | Orrville, OH |
| Ohio | Orwell | Orwell, OH |
| Ohio | Osgood | Osgood, OH |
| Ohio | Ostrander | Ostrander, OH |
| Ohio | Ottawa | Ottawa, OH |
| Ohio | Ottoville | Ottoville, OH |
| Ohio | Otway | Otway, OH |
| Ohio | Overpeck | Overpeck, OH |
| Ohio | Owensville | Owensville, OH |
| Ohio | Oxford | Oxford, OH |
| Ohio | Painesville | Painesville, OH |
| Ohio | Palestine | Palestine, OH |
| Ohio | Pandora | Pandora, OH |
| Ohio | Paris | Paris, OH |
| Ohio | Parkman | Parkman, OH |
| Ohio | Parma | Parma, OH |
| Ohio | Pataskala | Pataskala, OH |
| Ohio | Patriot | Patriot, OH |
| Ohio | Paulding | Paulding, OH |
| Ohio | Payne | Payne, OH |