| Code | Name | Region |
|---|---|---|
| USAFQ | Afton | VA |
| USAFO | Afton | WY |
| USXBL | Agawam | MA |
| USUAX | Agoura | CA |
| USAGH | Agoura Hills | CA |
| USA2G | Agua Dulce | CA |
| UST7X | Agua Dulce | TX |
| USGKG | Aguanga | CA |
| USAHE | Ahoskie | NC |
| USAH2 | Ahsahka | ID |
| USAIE | Aiea (oahu) | HI |
| USAIK | Aiken | SC |
| USYAY | Ailey | GA |
| USAW2 | Ainsworth | NE |
| USA2M | Airmont | NY |
| USAYH | Airway Heights | WA |
| USKN9 | Aitkin | MN |
| USAJ9 | Ajo | AZ |
| USA9D | Adelphi | MD |
| USAHP | Adelphia | NJ |
| USAGE | Adger | AL |
| USRZU | Adkins | TX |
| USADG | Adrian | MI |
| USAI4 | Adrian | MN |
| USAQA | Adrian | OH |
| USUAO | Adrian | OR |
| USAD9 | Adrian | PA |
| US5AN | Adrian | TX |
| USDIA | Adrian | WI |
| USAR8 | Adrian | WV |
| USA2D | Advance | IN |
| USAVX | Advance | MO |
| USUAR | Advance | NC |
| USAFF | Affton | MO |
| USAFK | Afognak | AK |
| USAF5 | Afton | IA |
| USAF9 | Afton | MI |
| USFJT | Afton | MN |
| USUAJ | Adams Run | SC |
| USDST | Adamston | WV |
| USAN6 | Adamstown | MD |
| USAEJ | Adamstown | PA |
| US6LA | Adamsville | AL |
| USUAM | Adamsville | TN |
| USADD | Addis | LA |
| USADS | Addison | AL |
| USUAP | Addison | IL |
| USIAB | Addison | ME |
| USYAI | Addison | MI |
| USXDS | Addison | NY |