| Code | Name | Region |
|---|---|---|
| USPFT | Pfafftown | NC |
| USPFV | Pflugerville | TX |
| USPFX | Pharr | TX |
| USVPH | Phelan | CA |
| USIPP | Phelps | KY |
| USPPX | Phelps | NY |
| USPHA | Phenix City | AL |
| USPCB | Phil Campbell | AL |
| USPXX | Philadelphia | MS |
| USPDP | Philadelphia | NY |
| USPHL | Philadelphia | PA |
| USPNE | Philadelphia North East Apt | PA |
| US2PB | Petersboro | UT |
| USPSG | Petersburg | AK |
| USPB8 | Petersburg | IN |
| USRUG | Petersburg | KY |
| USM94 | Petersburg | MI |
| USPBP | Petersburg | NE |
| USUPG | Petersburg | NJ |
| USTSB | Petersburg | NY |
| USPBU | Petersburg | PA |
| USTSR | Petersburg | TN |
| USPBB | Petersburg | TX |
| USPTB | Petersburg | VA |
| USPGC | Petersburg | WV |
| USPB2 | Petersburg, Menard | IL |
| USM7A | Petersham | MA |
| USPNF | Peterson's Point | AK |
| USPET | Petoskey | MI |
| USEUM | Petroleum | IN |
| USEJI | Petrolia | CA |
| USPEO | Petrolia | PA |
| USPYS | Perryopolis | PA |
| USXKQ | Perrysburg | OH |
| USPYV | Perrysville | OH |
| USEYN | Perryton | TX |
| USKPV | Perryville | AK |
| USPYI | Perryville | MD |
| USPYX | Perryville | MO |
| USPAY | Perth Amboy | NJ |
| USVYS | Peru | IL |
| USGUS | Peru | IN |
| USP6N | Peru | ME |
| USPGU | Peru | NY |
| US7PE | Peru | VT |
| USYPQ | Pescadero | CA |
| USP2N | Peshastin | WA |
| USPSH | Peshtigo | WI |
| USPT4 | Petal | MS |
| USPUM | Petaluma | CA |