O
- Oakfield (Genesee County)
- Ogden (Monroe County)
- Ohio (Herkimer County)
- Olean (Cattaraugus County)
- Olive (Ulster County)
- Oneonta (Otsego County)
- Onondaga (Onondaga County)
- Ontario (Wayne County)
- Oppenheim (Fulton County)
- Orange (Schuyler County)
- Orangetown (Rockland County)
- Orangeville (Wyoming County)
- Orchard Park (Erie County)
- Orleans (Jefferson County)
- Orwell (Oswego County)
- Osceola (Lewis County)
- Ossian (Livingston County)
- Ossining (Westchester County)
- Oswegatchie (St. Lawrence County)
- Oswego (Oswego County)
- Otego (Otsego County)
- Otisco (Onondaga County)
- Otsego (Otsego County)
- Otselic (Chenango County)
- Otto (Cattaraugus County)
- Ovid (Seneca County)
- Owasco (Cayuga County)
- Owego (Tioga County)
- Oxford (Chenango County)
- Oyster Bay (Nassau County)
Read more about this topic: List Of Towns In New York