| Code | Name | Region |
|---|---|---|
| USJYR | Argyle | NY |
| US9AR | Argyle | TX |
| USA3Y | Argyle | WI |
| USID7 | Arimo | ID |
| USIOA | Arion | IA |
| USA3R | Aristes | PA |
| USRIU | Ariton | AL |
| USADA | Arkadelphia | AR |
| USASC | Arkansas City | AR |
| USARK | Arkansas City | KS |
| USKOM | Arkoma | OK |
| USNK7 | Arkport | NY |
| USXAI | Arlee | MT |
| USARR | Arleta | CA |
| USARL | Arley | AL |
| USR99 | Arlington | AL |
| USAGZ | Arlington | AZ |
| USARD | Arlington | GA |
| USAHB | Archbald | PA |
| USARO | Archbold | OH |
| USXAZ | Archdale | NC |
| US6AR | Archie | MO |
| USAKV | Arcola | IL |
| USAXL | Arcola | IN |
| USXAY | Arcola | LA |
| USAR4 | Arcola | TX |
| USARC | Arctic Village | AK |
| USAYY | Arden | NC |
| USARH | Arden Hills | MN |
| USZAA | Ardena | NJ |
| USAR9 | Ardmore | AL |
| USADM | Ardmore | OK |
| USDM6 | Ardmore | PA |
| USAME | Ardmore | TN |
| USADY | Ardsley | NY |
| US4RN | Arena | WI |
| USARS | Arenzville | IL |
| US7AR | Argenta | IL |
| USYAS | Aransas Pass | TX |
| USOZP | Arapaho | OK |
| USAAE | Arapahoe | CO |
| USXRP | Arapahoe | NE |
| USA2A | Ararat | VA |
| USA4A | Arbela | MO |
| USAV2 | Arbor Vitae | WI |
| USARU | Arbuckle | CA |
| USJBM | Arbutus | MD |
| USAYD | Arbyrd | MO |
| USAC2 | Arcade | NY |
| USJAR | Arcadia | CA |