| Code | Name | Region |
|---|---|---|
| USAO8 | Artois | CA |
| USXJW | Arundel | ME |
| USAVL | Arundel Village | MD |
| USAVA | Arvada | CO |
| USA8V | Arverne | NY |
| USAXI | Arvin | CA |
| USVZN | Arvonia | VA |
| USAS9 | Asbury | IA |
| USAH9 | Armagh | PA |
| USAXC | Armonk | NY |
| USAXE | Armorel | AR |
| USAO3 | Armour | SD |
| USAEZ | Armstrong | IA |
| USARM | Armuchee | GA |
| USDVZ | Arnaudville | LA |
| USZRG | Arnegard | ND |
| USOAR | Arnett | OK |
| USYAJ | Arnold | CA |
| USAZR | Arnold | MD |
| USAXF | Arnold | MO |
| USA99 | Arnold | NE |
| USAQL | Arnold | PA |
| USRNR | Arnolds Park | IA |
| US4AR | Aroda | VA |
| US6AP | Aroma Park | IL |
| USAQR | Aromas | CA |
| USRPI | Arpin | WI |
| USAE9 | Arrey | NM |
| USIGN | Arlington | IA |
| USRLG | Arlington | IL |
| USIGB | Arlington | IN |
| USZAT | Arlington | MA |
| USARE | Arlington | MN |
| USQAR | Arlington | NJ |
| USJIG | Arlington | NY |
| USARF | Arlington | OR |
| USAGT | Arlington | SD |
| USARJ | Arlington | TX |
| USARP | Arlington | VA |
| USXBC | Arlington | VT |
| USAZZ | Arlington | WA |
| USXBM | Arlington | WI |
| USJLH | Arlington Heights | IL |
| USAGW | Arlington, Houston | TN |
| USAT3 | Arlington, Knox | TN |
| USIGT | Arlington, Shelby | TN |
| USAAP | Arlington/baltimore | MD |
| USAAK | Armada | MI |
| USXBB | Argo | IL |
| USAGJ | Argos | IN |