| Code | Name | Region |
|---|---|---|
| US9ME | Manset | ME |
| USXMW | Mansfield | AR |
| USMSF | Mansfield | GA |
| USAFD | Mansfield | LA |
| USMNS | Mansfield | MA |
| USLFM | Mansfield | MO |
| USMFD | Mansfield | OH |
| USMAS | Mansfield | PA |
| USS7F | Mansfield | SD |
| USMFL | Mansfield | TX |
| USMC8 | Mansfield Center | CT |
| USMON | Manson | IA |
| USYMN | Manson | WA |
| USZMY | Manheim Center | NY |
| USMXA | Manila | AR |
| USMBL | Manistee | MI |
| USISQ | Manistique | MI |
| USILT | Manito | IL |
| USMS8 | Manitou Springs | CO |
| USIZW | Manitowish Waters | WI |
| USMTW | Manitowoc | WI |
| USMKT | Mankato | MN |
| USMLY | Manley Hot Springs | AK |
| USAIU | Manlius | NY |
| US9ML | Manly | IA |
| USYNF | Mannford | OK |
| USIA2 | Manning | IA |
| USIFG | Manning | ND |
| USMNG | Manning | SC |
| USMT7 | Mannington | NJ |
| USQNG | Mannington | WV |
| USAIM | Mannington Mills | NJ |
| USOMZ | Manns Choice | PA |
| USNKR | Manchester | NY |
| USNSK | Manchester | OH |
| USUMZ | Manchester | OK |
| USYMC | Manchester | PA |
| USAQS | Manchester | TN |
| USYMX | Manchester | VT |
| USMCR | Manchester | WA |
| USMNJ | Manchester Center | VT |
| USMCS | Mancos | CO |
| USNDN | Mandan | ND |
| USNDR | Mandarin | FL |
| USMAB | Mandeville | LA |
| USMH8 | Manhasset | NY |
| USHM8 | Manhattan | IL |
| USMHK | Manhattan | KS |
| US2MH | Manhattan | MT |
| USNXH | Manhattan | NV |