- Old Place Windmills
- Oak Flat
- Ora
- Ogden
- Oaks
- Old Airport Road Colonia
- Old Houston Highway Colonia
- Olmos
- Orangedale
- Ocker
- Oenaville
- Oscar
- Owl Creek
- Oak Island
- Oakland Estates
- Oak Grove
- Old Boston
- Old Salem
- Old Union
- Oakbrook Estates
- Oakland
- Old Brazoria
- Orozimbo
- Otey
- Old Beekley Place
- Old Corbett Place
- Old Edith Lochausen Place
- Old Oscar Nance Place
- Old Parker Place
- Old Reed Place