| Code | Name | Region |
|---|---|---|
| USYLM | Mahanoy City | PA |
| US3MH | Maher | CO |
| US6SN | Madison | NH |
| USQMJ | Madison | NJ |
| USMO7 | Madison | NY |
| USAAL | Madison | OH |
| USDQS | Madison | PA |
| USMO9 | Madison | SC |
| USXMD | Madison | SD |
| USMAO | Madison | TN |
| USMS4 | Madison | VA |
| USMSN | Madison | WI |
| USQMD | Madison | WV |
| USMSH | Madison Heights | MI |
| USMH5 | Madison Heights | VA |
| USYMD | Madison Park | WA |
| USMDJ | Madison-madras Apt | OR |
| USMVQ | Madisonville | KY |
| USINV | Madisonville | LA |
| USIOE | Madisonville | TN |
| USDIX | Madisonville | TX |
| USMDM | Madras | OR |
| USMAD | Madawaska | ME |
| US2MB | Madbury | NH |
| USDOC | Maddock | ND |
| USME6 | Madeira | OH |
| USEIF | Madeira Beach | FL |
| USMDA | Madelia | MN |
| USMAE | Madera | CA |
| USMIL | Madill | OK |
| USMAZ | Madison | AL |
| USMPE | Madison | CT |
| USDIC | Madison | FL |
| USMDS | Madison | GA |
| USMZX | Madison | IL |
| USMDN | Madison | IN |
| USMYY | Madison | ME |
| USMA8 | Madison | MN |
| USM3D | Madison | MO |
| USMSM | Madison | MS |
| USMDI | Madison | NC |
| USMSB | Madison | NE |
| USXIF | Macedonia | OH |
| USMKP | Maceo | KY |
| US8U6 | Machen | GA |
| USMP5 | Machesney Park | IL |
| USACI | Machias | ME |
| US9MP | Machiasport | ME |
| USMCD | Mackinac Island | MI |
| USKWZ | Mackinaw | IL |