Towns
| State | City/Town | Town Title |
|---|---|---|
| Texas | Oak Ridge North | Oak Ridge North, TX |
| Texas | Oakhurst | Oakhurst, TX |
| Texas | Oakland | Oakland, TX |
| Texas | Oakville | Oakville, TX |
| Texas | Oakwood | Oakwood, TX |
| Texas | Odell | Odell, TX |
| Texas | Odem | Odem, TX |
| Texas | Odessa | Odessa, TX |
| Texas | Odonnell | Odonnell, TX |
| Texas | Oglesby | Oglesby, TX |
| Texas | Oilton | Oilton, TX |
| Texas | Oklaunion | Oklaunion, TX |
| Texas | Old Glory | Old Glory, TX |
| Texas | Old Ocean | Old Ocean, TX |
| Texas | Olden | Olden, TX |
| Texas | Olmito | Olmito, TX |
| Texas | Olney | Olney, TX |
| Texas | Olton | Olton, TX |
| Texas | Omaha | Omaha, TX |
| Texas | Onalaska | Onalaska, TX |
| Texas | Orange | Orange, TX |
| Texas | Orange Grove | Orange Grove, TX |
| Texas | Orangefield | Orangefield, TX |
| Texas | Orchard | Orchard, TX |
| Texas | Ore City | Ore City, TX |