| Code | Name | Region |
|---|---|---|
| USIWN | Merrittstown | PA |
| USMH7 | Merry Hill | NC |
| USM7S | Mershon | GA |
| USM7N | Merton | WI |
| USERT | Mertzon | TX |
| USMZP | Mertztown | PA |
| USMQA | Mesa | AR |
| USMSC | Mesa | AZ |
| USJME | Mesa | CO |
| USEZS | Mesa | WA |
| USZPN | Meshoppen | PA |
| USVSK | Mesick | MI |
| USMSX | Mesilla Park | NM |
| USME5 | Meredith | NY |
| USOIS | Meredosia | IL |
| USMRD | Meriden | CT |
| USMN7 | Meriden | KS |
| USEIQ | Meriden | MN |
| USMZA | Meridian | CA |
| USMJA | Meridian | ID |
| USMEI | Meridian | MS |
| USM3R | Meridian | TX |
| USMLZ | Meridianville | AL |
| USIJO | Merino | CO |
| USJEK | Merkel | TX |
| USMNU | Mermentau | LA |
| USKXM | Merom | IN |
| USMEW | Merriam | KS |
| USMER | Merrick | NY |
| USMZR | Merrifield | MN |
| USVM4 | Merrifield | VA |
| US9MR | Merrill | IA |
| USMMD | Merrill | MI |
| USMZQ | Mentone | CA |
| USNNE | Mentone | IN |
| USMX3 | Mentone | TX |
| USZTO | Mentor | MN |
| USMEA | Mentor | OH |
| USMQU | Mequon | WI |
| USZXE | Mer Rouge | LA |
| USMXP | Meraux | LA |
| USMCE | Merced | CA |
| USMRS | Mercedes | TX |
| USMZ2 | Mercer | ME |
| USEZC | Mercer | MO |
| USMQX | Mercer | PA |
| USDMC | Mercer | WI |
| USMQZ | Mercer Island | WA |
| USMBP | Mercersburg | PA |
| USMVS | Mercerville | NJ |