| Code | Name | Region |
|---|---|---|
| USPF5 | Pigeon Falls | WI |
| USYPF | Pigeon Forge | TN |
| USXPN | Phoenix | IL |
| USP2X | Phoenix | MD |
| USXH5 | Phoenix | NY |
| USONX | Phoenix | OR |
| US5JD | Phoenix | TX |
| USPXT | Phoenix Township | AR |
| USPXV | Phoenixville | PA |
| USPIC | Picacho | AZ |
| USPY5 | Picatinny Arsenal | NJ |
| USPCU | Picayune | MS |
| USP3R | Picher | OK |
| USLQK | Pickens | SC |
| USYKV | Pickensville | AL |
| USJPK | Pickering | MO |
| USPXQ | Pickerington | OH |
| USP3T | Pickstown | SD |
| USPQU | Pico Rivera | CA |
| USXPI | Piedmont | AL |
| USPVK | Piedmont | CA |
| USPIX | Piedmont | KS |
| USPHP | Philip | SD |
| USPPI | Philippi | WV |
| USIIP | Philipsburg | MT |
| USZPC | Philipsburg | PA |
| US8LH | Phillips | ME |
| USPH9 | Phillips | NE |
| USPJP | Phillips | WI |
| USPHJ | Phillipsburg | KS |
| USPB6 | Phillipsburg | MO |
| USPHI | Phillipsburg | NJ |
| USZPG | Phillipsburg | NY |
| USPH8 | Phillipston | MA |
| USPH3 | Philmont | NY |
| USPL6 | Philo | CA |
| USPJI | Philo | OH |
| USYPH | Philomath | OR |
| USPPP | Philpot | KY |
| US8PP | Phippsburg | ME |
| USP6H | Phoenicia | NY |
| USPHX | Phoenix | AZ |
| USPXI | Petrolia | TX |
| USPV7 | Pettisville | OH |
| USEQY | Petty | TX |
| USPVB | Pevely | MO |
| USPZE | Pewamo | MI |
| USPEW | Pewaukee | WI |
| USEYC | Pewee Valley | KY |
| USYPT | Peyton | CO |