| Code | Name | Region |
|---|---|---|
| USCEY | Murray | KY |
| US7MU | Murray | NE |
| USMUY | Murray | UT |
| USMRR | Murray Hill | NJ |
| USWQ2 | Murraysville | WV |
| USGGQ | Murrayville | GA |
| USRT3 | Murrells Inlet | SC |
| USMHQ | Murrieta | CA |
| USXYS | Murrysville | PA |
| USMMG | Murtaugh | ID |
| USMUT | Muscatine | IA |
| USUSH | Muscle Shoals | AL |
| USMUZ | Muscoda | WI |
| USUSG | Muskego | WI |
| USMKG | Muskegon | MI |
| US5MO | Muskegon Heights | MI |
| USMKO | Muskogee | OK |
| USUOB | Munford | AL |
| USM7F | Munford | TN |
| USUNF | Munfordville | KY |
| USUEM | Munger | MI |
| USM8D | Munich | ND |
| USMGS | Munising | MI |
| USUNV | Munnsville | NY |
| USMF9 | Munroe Falls | OH |
| USMUQ | Munster | IN |
| USMUS | Murchison | TX |
| USMR5 | Murdock | IL |
| USUDK | Murdock | MN |
| USYMK | Murdock | NE |
| USFB3 | Murfreesboro | AR |
| USMUC | Murfreesboro | NC |
| USMFU | Murfreesboro | TN |
| USZMU | Murphy | NC |
| USURP | Murphy | OR |
| USMU8 | Murphy | TX |
| USMS5 | Murphys | CA |
| USMKZ | Mukwonago | WI |
| USEYQ | Mulberry | AR |
| USMUF | Mulberry | FL |
| USMU9 | Muldoon | TX |
| USZMW | Muldrow | OK |
| USMUH | Muleshoe | TX |
| USUGM | Mulga | AL |
| USMU7 | Mulino | OR |
| USMHN | Mullen | NE |
| USMU3 | Mullens | WV |
| USMHJ | Mullica Hill | NJ |
| USRMU | Mulliken | MI |
| USMXU | Mullins | SC |