| Code | Name | Region |
|---|---|---|
| USGMV | Monument Valley Gldngs | UT |
| USMU2 | Moodus | CT |
| USMD7 | Moody | AL |
| USOOY | Moody | TX |
| USMO3 | Mooers | NY |
| USM2F | Mooers Forks | NY |
| USNIP | Moon | PA |
| USOIO | Monticello | IN |
| USMOC | Monticello | KY |
| USM8L | Monticello | ME |
| USOTC | Monticello | MN |
| USMCZ | Monticello | MS |
| USMSV | Monticello | NY |
| USMXC | Monticello | UT |
| USIEO | Monticello | WI |
| USZGI | Montmorenci | IN |
| USURF | Montour Falls | NY |
| USMBC | Montoursville | PA |
| USIUW | Montpelier | ID |
| USOPQ | Montpelier | IN |
| USMMP | Montpelier | OH |
| USXIX | Montpelier | VA |
| USMPI | Montpelier | VT |
| USMT8 | Montreal | MO |
| USM2T | Montreal | OH |
| USOZ9 | Montrose | AL |
| USXIL | Montgomery | IL |
| USOGM | Montgomery | IN |
| US3MG | Montgomery | LA |
| USMGH | Montgomery | MN |
| USMGJ | Montgomery | NY |
| USNGY | Montgomery | OH |
| USQMG | Montgomery | PA |
| USYGY | Montgomery | TN |
| USMG6 | Montgomery | TX |
| US7MG | Montgomery | VT |
| USOTE | Montgomery | WV |
| USGZY | Montgomery Center | VT |
| USM4G | Montgomery City | MO |
| USNMV | Montgomery Village | MD |
| USUXG | Montgomeryville | PA |
| USMOQ | Monticello | AR |
| USVMQ | Monticello | FL |
| USMQC | Monticello | GA |
| USMXO | Monticello | IA |
| USMQD | Monticello | IL |
| USMTB | Montebello | CA |
| USMB6 | Montebello | NY |
| USZMO | Montecito | CA |
| USM4O | Montello | PA |