- Onota
- Oakland
- Old Saugatuck
- Old Squaw Skin Landing
- Overisel
- Oxbow
- Orangeville
- Orangeville Island
- Oakbrook Mobile Home Park
- Oakside Mobile Home Park
- Oakview Estates Mobile Home Park
- Ontario Place Mobile Home Park
- Orchard View Estates
- Oxbow
- Oak Forest Mobile Home Park
- Old Mill Gardens
- Orchard Park
- Ojibwa Island
- Orchard Beach
- Oak Ridge
- Oak Island Mobile Home Park
- Oak Bluff Estates Mobile Home Park
- Ogontz
- Oneida Center
- Oden Island
- Orchard Cove Manufactured Home Community
- Oberlin
- Oak Park
- Oakley
- Olivet