| Code | Name | Region |
|---|---|---|
| USPDG | Playa Vista | CA |
| USJLZ | Plaza | ND |
| USPSW | Plainview | OH |
| USPVW | Plainview | TX |
| USPVI | Plainville | CT |
| USPVG | Plainville | GA |
| USIN8 | Plainville | IN |
| USIIB | Plainville | KS |
| USXKV | Plainville | MA |
| USZG7 | Plainville | NY |
| USPNW | Plainwell | MI |
| USPZX | Plaistow | NH |
| USJDP | Plandome | NY |
| USPK7 | Plankinton | SD |
| USIP2 | Plano | IA |
| USPNO | Plano | IL |
| USPLZ | Plano | TX |
| USPCI | Plant City | FL |
| USPL9 | Plantation | FL |
| USYIT | Plantation | FL |
| USLRL | Plantersville | MS |
| US2PV | Plantersville | TX |
| USPFE | Plainfield | CT |
| USNLF | Plainfield | IA |
| USPLI | Plainfield | IL |
| USPAF | Plainfield | IN |
| USFP8 | Plainfield | MA |
| USYPD | Plainfield | NH |
| USPLF | Plainfield | NJ |
| USIFI | Plainfield | OH |
| USPF2 | Plainfield | TN |
| USPF4 | Plainfield | VT |
| USLNF | Plainfield | WI |
| USXPF | Plainfield Center | NY |
| USPLS | Plains | GA |
| USP4L | Plains | KS |
| USLPY | Plains | PA |
| USPLJ | Plains | TX |
| USXKM | Plainsboro | NJ |
| USPVN | Plainview | MN |
| USPFW | Plainview | NE |
| USPVX | Plainview | NY |
| USPVQ | Pittsville | PA |
| USITV | Pittsville | WI |
| USPXY | Pixley | CA |
| USP9C | Placedo | TX |
| USPCC | Placentia | CA |
| USPVF | Placerville | CA |
| USEUU | Placida | FL |
| US9LA | Placitas | NM |