| Code | Name | Region |
|---|---|---|
| USMOS | Moses Point | AK |
| USEIB | Mosheim | TN |
| USYMR | Mosier | OR |
| USINX | Mosinee | WI |
| USMJN | Moss | TN |
| USZGA | Moss Beach | CA |
| USMLG | Moss Landing | CA |
| USMOG | Moss Point | MS |
| USMVJ | Mossville | IL |
| US89M | Mossyrock | WA |
| USMOF | Motley | MN |
| USMLL | Mottville | MI |
| USMUW | Moulton | AL |
| USX3L | Moulton | TX |
| USQUG | Moultonborough | NH |
| USMGR | Moultrie | GA |
| USOUD | Mound | MN |
| USMW6 | Morrow | OH |
| US4MT | Morse | TX |
| USMB3 | Morse Bluff | NE |
| USMTI | Morton | IL |
| USJMN | Morton | MN |
| USMNQ | Morton | MS |
| USJZN | Morton | PA |
| USZMT | Morton | TX |
| USOT3 | Morton | WA |
| USMGV | Morton Grove | IL |
| USMJJ | Mortons Gap | KY |
| USOQV | Morven | NC |
| USMW3 | Moscow | IA |
| USMJL | Moscow | ID |
| USZGC | Moscow | KS |
| USQMA | Moscow | PA |
| US9MW | Moscow | TN |
| USM7C | Moscow | TX |
| USMM4 | Moscow Mills | MO |
| USM9S | Mosel | WI |
| USIQS | Morris | PA |
| USMPA | Morris Plains | NJ |
| USMJE | Morrison | CO |
| USMMQ | Morrison | IL |
| USMJF | Morrison | TN |
| USM5V | Morrisonville | IL |
| US6MT | Morriston | FL |
| USMJG | Morristown | IN |
| USMW8 | Morristown | MN |
| USMMU | Morristown | NJ |
| USMRT | Morristown | NY |
| USITW | Morristown | OH |
| USMOR | Morristown | TN |