- Oakwood Beach
- Oakwood Estates Mobile Home Park
- Oakwood Heights Station
- Oakwood Terrace
- Oakwoods Mobile Home Court
- Oatka
- Obernburg
- Obi
- Occanum
- Occanum Falls Mobile Home Park
- Ocean Bay Park
- Ocean Beach
- Ocean Point
- Oceanside
- Oceola Lake
- Odell
- Odell Islands
- Odessa
- Ogden Center
- Ogden Island
- Ogdensburg
- Ohio
- Ohioville
- Oklahoma Beach
- Olcott
- Old Bethpage
- Old Brookville
- Old Central Bridge
- Old Chatham
- Old City