| Code | Name | Region |
|---|---|---|
| USP6P | Point Pleasant | NJ |
| USPPZ | Point Pleasant | WV |
| USGYU | Plymouth | VT |
| USP5Y | Plymouth | WA |
| USPMW | Plymouth | WI |
| USPMM | Plymouth Meeting | PA |
| USPL4 | Plympton | MA |
| USPOX | Poca | WV |
| USPXH | Pocahontas | AR |
| USPOH | Pocahontas | IA |
| USPH2 | Pocahontas | MS |
| USQPH | Pocahontas | TN |
| USPHH | Pocahontas | TN |
| USPJC | Pocasset | MA |
| USOAT | Pocatalico | WV |
| USPIH | Pocatello | ID |
| USPCL | Pocola | OK |
| USPKM | Pocomoke City | MD |
| USPOR | Pocono Manor | PA |
| US9PP | Pocono Pines | PA |
| USP9S | Pocono Summit | PA |
| USOTK | Poestenkill | NY |
| USPWD | Plentywood | MT |
| USQOV | Plover | IA |
| USPLW | Plover | WI |
| USPJU | Pluckemin | NJ |
| USPUR | Plumerville | AR |
| USPUV | Plumsteadville | PA |
| USPYT | Plymouth | CA |
| USYMU | Plymouth | CT |
| USPMF | Plymouth | FL |
| USYIQ | Plymouth | IL |
| USPLY | Plymouth | IN |
| USPYM | Plymouth | MA |
| US8PY | Plymouth | ME |
| USUXY | Plymouth | MI |
| USPYO | Plymouth | MN |
| USXKN | Plymouth | NC |
| USPVH | Plymouth | NH |
| USPLH | Plymouth | OH |
| USPMY | Plymouth | PA |
| USXOU | Plymouth | UT |
| USPAP | Pleasant Plain | OH |
| USPPL | Pleasant Plains | IL |
| USXPP | Pleasant Prairie | IA |
| USPLP | Pleasant Prairie | WI |
| USPZ6 | Pleasant Shade | TN |
| USPU7 | Pleasant Unity | PA |
| USPEY | Pleasant Valley | MO |
| USZHJ | Pleasant Valley | NY |