- Oakview
- Oakwood Acres
- Oakwood Mobile Home Park
- Oakwood Village
- Oberlin Beach
- Oceola
- Oco
- Odell
- Offenbacher Mobile Home Park
- Ogden
- Ogontz
- Ohio Furnace
- Ohio Shores
- Ohltown
- Oil Station
- Okeana
- Okey
- Okolona
- Olbers
- Old Fort
- Old Gore
- Old Town
- Olde Falls Village
- Olde Town Mobile Home Park
- Oldfield Estates
- Oldham
- Oldtown
- Oldtown Flats
- Olena
- Olentangy