| Ostby, ND (Township) |
| Osterdock, IA (City) |
| Ostrander, MN (City) |
| Ostrander, OH (Village) |
| Oswayo, PA (Borough) |
| Oswayo Township, PA (Township) |
| Oswegatchie, NY (Town) |
| Oswego, NY (Town) |
| Oswego, NY (City) |
| Oswego, IL (Village) |
| Oswego, KS (Township) |
| Oswego, KS (City) |
| Oswego County, NY (County) |
| Oswego Township, IL (Township) |
| Osyka, MS (Town) |
