- Old River-Winfree
- Old Saint Marys
- Old Salem
- Old Santa Elena
- Old Union
- Old Union
- Old Union
- Old Union
- Old Waverly
- Olde Oaks
- Olden
- Oldenburg
- Oldham
- Oldham
- Oldham
- Oletha
- Olfen
- Olin
- Olivarez
- Olivarez Colonia
- Olivarez Number 1 Colonia
- Olivarez Number 10 Colonia
- Olivarez Number 15 Colonia
- Olivarez Number 17 Colonia
- Olivarez Number 18 Colonia
- Olivarez Number 2 Colonia
- Olivarez Number 3 Colonia
- Olivarez Number 4 Colonia
- Olivarez Number 5 Colonia
- Olivarez Number 6 Colonia