| Castleton Township, MI (Township) |
| Castlewood, SD (Township) |
| Castlewood, SD (City) |
| Castor, LA (Village) |
| Castor, MO (Township) |
| Castorland, NY (Village) |
| Castro County, TX (County) |
| Castroville, TX (City) |
| Caswell, ME (Town) |
| Caswell Beach, NC (Town) |
| Caswell County, NC (County) |
| Caswell Town, WI (Town) |
| Catahoula Parish, LA (County) |
| Catalina At Winkler Preserve Community Development District, FL (CDD) |
| Catasauqua, PA (Borough) |
