| Jupiter Inlet Colony, FL (Town) |
| Jupiter Island , FL (Town) |
| Jurupa Valley, CA (City) |
| Justice, IL (Village) |
| Justin, TX (City) |
| K-Bar Ranch Community Development District, FL (CDD) |
| Kabetogama, MN (Township) |
| Kachemak, AK (City) |
| Kadoka, SD (City) |
| Kahlotus, WA (City) |
| Kahoka, MO (City) |
| Kake, AK (City) |
| Kaktovik, AK (City) |
| Kalama, WA (City) |
| Kalamazoo, MI (City) |
