| Code | Name | Region |
|---|---|---|
| USOOU | Moosup | CT |
| USMJM | Mora | MN |
| USMMA | Mora | NM |
| USQMO | Moraga | CA |
| USMRE | Moraine | OH |
| USMX7 | Moran | WY |
| USMJS | Morattico | VA |
| USQOR | Moravia | IA |
| USVIJ | Moravia | NY |
| USMF4 | Moravian Falls | NC |
| USMHR | Morehead | KY |
| USMRH | Morehead City | NC |
| USYRE | Morehouse | MO |
| US9OH | Moreland Hills | OH |
| USONJ | Morenci | AZ |
| USMQR | Morenci | MI |
| USMV4 | Moreno Valley | CA |
| USM7P | Moon Township | PA |
| USMOO | Moonachie/new Jersey | NJ |
| USQMP | Moonstown | PA |
| USOOF | Moore | OK |
| USMBW | Moore | SC |
| USQMF | Moore Haven | FL |
| USMF2 | Moorefield | KY |
| USMF3 | Moorefield | WV |
| USOED | Mooreland | OK |
| USMQE | Moores Mill | NY |
| USOBO | Mooresboro | NC |
| USOUB | Mooresburg | TN |
| USMRJ | Moorestown | NJ |
| USOOR | Moorestown | PA |
| USMYZ | Mooresville | IN |
| US2MV | Mooresville | MO |
| USXJK | Mooresville | NC |
| USM3O | Mooresville | TN |
| USXIH | Moorhead | MN |
| USMPF | Moorlands | WA |
| USMBH | Montrose | CA |
| USMTJ | Montrose | CO |
| US4MO | Montrose | IA |
| USME3 | Montrose | MN |
| USQMR | Montrose | PA |
| USKMX | Montross | VA |
| USQMV | Montvale | NJ |
| USM8V | Montvale | VA |
| USMBM | Montville | CT |
| USMDB | Montville | NJ |
| USZPQ | Montz | LA |
| USMEB | Monument | CO |
| USJUM | Monument | KS |