| Code | Name | Region |
|---|---|---|
| USPV8 | Palenville | NY |
| USPCZ | Pace | FL |
| USZE4 | Pacheco | CA |
| USPCW | Pachuta | MS |
| USAC3 | Pacific | MO |
| USPF8 | Pacific | WA |
| USPFC | Pacific City | OR |
| USICG | Pacific Grove | CA |
| USPJ8 | Pacific Junction | IA |
| USPPH | Pacific Palisades | CA |
| USPFQ | Pacifica | CA |
| USPBK | Pack Creek | AK |
| USPUQ | Pacoima | CA |
| USZG9 | Pacolet | SC |
| USPCY | Paden City | WV |
| USPAH | Paducah | KY |
| USXKG | Paducah | TX |
| USPFA | Paf Warren | AK |
| USPGA | Page | AZ |
| USPGE | Pagedale | MO |
| USPQR | Pageland | SC |
| USOSF | Oxford | NE |
| USOXW | Oxford | NJ |
| USOX3 | Oxford | NY |
| USOXD | Oxford | OH |
| USZXO | Oxford | PA |
| USOFQ | Oxford | WI |
| USOXY | Oxly | MO |
| USOXN | Oxnard | CA |
| USOXR | Oxnard-ventura Apt | CA |
| USOXH | Oxon Hill | MD |
| USOYB | Oyster Bay | NY |
| USYRC | Oyster Creek | TX |
| USOZR | Ozark | AL |
| USOZK | Ozark | AR |
| USORK | Ozark | MO |
| USOZA | Ozona | TX |
| USZ6O | Ozone | AR |
| USOZO | Ozone Park/queens/new York | NY |
| USZPO | Pablo | MT |
| USPBT | Pabst | GA |
| USOWJ | Owensville | IN |
| USOWV | Owensville | MO |
| USQOW | Owenton | KY |
| USOW7 | Owings | MD |
| USOWI | Owings Mills | MD |
| USO2W | Owingsville | KY |
| US2OH | Owls Head | ME |
| USOWO | Owosso | MI |
| USOXO | Oxford | AL |