- Oakhaven
- Oakland
- Oakland Heights
- Oaklawn
- Oakridge Estates
- Oakwood
- Oark
- Odell
- Oden
- Offutt Landing
- Ogden
- Ogemaw
- Oil Trough
- Okane Island
- Okay
- Okolona
- Ola
- Old Alabam
- Old Austin
- Old Bonnerdale
- Old Botkinburg
- Old Buffalo
- Old Cove
- Old De Roche
- Old Grand Glaise
- Old Hickory
- Old Jenny Lind
- Old Joe
- Old Lapile
- Old Lexington