| Code | Name | Region |
|---|---|---|
| USMP7 | Mediapolis | IA |
| USVMB | Medicine Bow | WY |
| USJMI | Medicine Lodge | KS |
| USMQW | Mcrae | GA |
| USHYT | Mcsherrystown | PA |
| USMVT | Mcveytown | PA |
| USDCM | Mcwilliams | AL |
| USM9E | Mead | CO |
| USMD4 | Mead | NE |
| USM2E | Mead | OK |
| USME8 | Mead | WA |
| US4MA | Meade | KS |
| USM6B | Meadow Bridge | WV |
| USMWD | Meadow Lands | PA |
| USJJQ | Meadows Of Dan | VA |
| USEOP | Meadows Place | TX |
| USMEJ | Meadville | PA |
| USQMS | Means | KY |
| USM3I | Meansville | GA |
| USMBN | Mebane | NC |
| USMEX | Mecca | CA |
| USKMC | Mecca | IN |
| USEAZ | Mechanic Falls | ME |
| USMK2 | Mckenzie | AL |
| USKZE | Mckenzie | ND |
| USUQX | Mckenzie | TN |
| USMLA | Mckinley Park | AK |
| USKNY | Mckinleyville | CA |
| USMCT | Mckinney | TX |
| USMK4 | Mckittrick | CA |
| USXQM | Mclean/washington, D.c. | VA |
| USIMQ | Mcleansboro | IL |
| USQMC | Mcleansville | NC |
| USC3U | Mclouth | KS |
| USEHJ | Mcmechen | WV |
| USMMW | Mcmillin | WA |
| USMMC | Mcminnville | OR |
| USRNC | Mcminnville | TN |
| USMCM | Mcmurray | PA |
| USMRX | Mcnary | OR |
| USJIL | Mcneil | TX |
| USMPR | Mcpherson | KS |
| USQNY | Mcqueeney | TX |
| USMCF | Mcfarland | CA |
| USMF6 | Mcfarland | WI |
| USMZ3 | Mcgaheysville | VA |
| USMWK | Mcgaw Park | IL |
| USGEH | Mcgehee | AR |
| USMCG | Mcgrath | AK |
| USM64 | Mcgraw | NY |