- Otter Lake
- Owendale
- Owasso
- Oil City
- Old Oak Trails Estates Mobile Home Park
- Olson
- Oakridge Estates Mobile Home Park
- Oakwood Mobile Home Community
- Oldport
- Ottawa
- Oaks Mobile Home Park
- Oxbow
- Oxbow Park
- Oak Grove
- Oakland Estates Mobile Home Park
- Oakwood
- Oxbow
- Oaklawn Beechwood
- Olive Center
- Ottawa Center
- Ottogan Mobile Home Estates
- Ocqueoc
- Orchard
- Orchard Point
- Ogemaw Springs
- Ojibway Island
- Orr
- Old Victoria Historic Townsite
- Orono
- Oakwood