| Code | Name | Region |
|---|---|---|
| USRIF | Richfield | UT |
| USQPC | Richfield | WI |
| USD5F | Richfield Springs | NY |
| USRFR | Richford | VT |
| USRG2 | Richgrove | CA |
| USR4L | Richland | GA |
| USRH7 | Richland | IA |
| USRIQ | Richland | MI |
| USRRM | Richland | MO |
| USRJL | Richland | MS |
| USQCL | Richland | NY |
| USYGT | Richland | OH |
| USIHL | Richland | OR |
| USRZK | Richland | PA |
| USRLD | Richland | WA |
| USRHO | Rhode Island | NY |
| USRH3 | Rhodesdale | MD |
| USODP | Rhodhiss | NC |
| USRBM | Rhome | TX |
| USRLO | Rialto | CA |
| USRC3 | Rice | MN |
| USRJI | Rice | TX |
| US2V2 | Rice | VA |
| USRIE | Rice Lake | WI |
| USRCG | Riceboro | GA |
| USP44 | Riceville | IA |
| USICV | Riceville | TN |
| USRHK | Rich Creek | VA |
| USRLX | Rich Hill | MO |
| USZE9 | Rich Square | NC |
| USR4N | Richardson | KY |
| USRIN | Richardson | TX |
| USRCJ | Richardton | ND |
| USRQC | Richboro | PA |
| USRXJ | Richburg | SC |
| USRTJ | Retsil | WA |
| USRT6 | Retsof | NY |
| USRUJ | Reunion | FL |
| USV8R | Reva | SD |
| USREZ | Revere | MA |
| USRE2 | Revillo | SD |
| USREX | Rex | GA |
| USRBI | Rexburg | ID |
| USRXK | Rexford | KS |
| USRXF | Rexford | MT |
| US4EX | Rexford | NY |
| USREY | Reynolds | GA |
| US4RD | Reynolds | IL |
| USRYQ | Reynolds | IN |
| USRYG | Reynoldsburg | OH |