- Oakland Ridge Mobile Home Park
- Oakville
- Ocean Bay Park
- Old Mastic
- Orient Point
- Oak Beach
- Oaks Corners
- Obernburg
- Old Forge
- Olivebridge
- Olmstedville
- Ontario
- Orangeburg, Saratoga
- Orwell
- Oswegatchie
- Otto
- Ouaquaga
- Owls Head
- Oxbow
- Ozone Park
- Oakfield
- Ocean Beach
- Ogdensburg
- Olcott
- Old Bethpage
- Old Brookville
- Old Field
- Old Westbury
- Olean
- Oneida