| Code | Name | Region |
|---|---|---|
| USPNB | Pontoon Beach | IL |
| USPOK | Pontotoc | MS |
| USYY2 | Pony | MT |
| USPOZ | Pooler | GA |
| US9PO | Poolville | TX |
| USPMP | Pope | MS |
| USPV9 | Pope Valley | CA |
| USPVY | Pope Vanoy | AK |
| USOPZ | Poplar | MT |
| USPOF | Poplar Bluff | MO |
| USOBZ | Poplar Branch | NC |
| US8AA | Poplar Grove | IL |
| USPOS | Polson | MT |
| USOYZ | Pomeroy | IA |
| USPX3 | Pomeroy | OH |
| US2PM | Pomeroy | PA |
| USPO6 | Pomeroy | WA |
| USPFR | Pomfret | CT |
| USO4F | Pomfret | MD |
| USPFF | Pomfret Center | CT |
| USPQC | Pomona | CA |
| USPQO | Pomona | IL |
| USPMO | Pomona | MO |
| USPMA | Pomona | NY |
| USPPM | Pompano Beach | FL |
| USPO8 | Pompton | NJ |
| USP7L | Pompton Lakes | NJ |
| USPMJ | Pompton Plains | NJ |
| USPNC | Ponca City | OK |
| US4NM | Ponce De Leon | FL |
| USOPS | Poncha Springs | CO |
| USPCS | Ponchatoula | LA |
| USPP3 | Point Pleasant Beach | NJ |
| USPRT | Point Retreat | AK |
| US9IU | Point Reyes Station | CA |
| USPRS | Point Roberts | WA |
| USOW4 | Point Wells | WA |
| USPHC | Pointe A La Hache | LA |
| USPXL | Polacca | AZ |
| USZE6 | Poland | ME |
| USYXD | Poland | NY |
| USQPD | Poland | OH |
| USPLD | Poland Spring | ME |
| USS6O | Polar | WI |
| USPG7 | Polk | PA |
| USP3K | Polk City | FL |
| USPOQ | Polk Inlet | AK |
| USNKK | Polkton | NC |
| USP2O | Pollock | LA |
| US9PL | Pollock Pines | CA |