| Code | Name | Region |
|---|---|---|
| USRKK | Ronkonkoma | NY |
| USROJ | Ronks | PA |
| USRO3 | Roodhouse | IL |
| USRPV | Roopville | GA |
| USROL | Roosevelt | UT |
| USRLT | Roosevelt | WA |
| USRVT | Rooseveltown | NY |
| USROO | Roosville | MT |
| USR34 | Rootstown | OH |
| USNCW | Roper | NC |
| USRVP | Ropesville | TX |
| USRZA | Rosalia | WA |
| USRSZ | Rosamond | CA |
| USRK2 | Rosanky | TX |
| USRSJ | Rosario | WA |
| USRK3 | Rolla | KS |
| USRLA | Rolla | MO |
| USRQL | Rolla | ND |
| USRFY | Rolling Fork | MS |
| US5RH | Rolling Hills | CA |
| USRHJ | Rolling Hills Estates | CA |
| USRLM | Rolling Meadows | IL |
| USRPA | Rolling Prairie | IN |
| USRJS | Rollins | MT |
| USR3O | Rollinsford | NH |
| USFAL | Roma | TX |
| USRMG | Rome | GA |
| USRME | Rome | NY |
| USRQM | Rome | OK |
| USREO | Rome | OR |
| USRMO | Romeo | MI |
| USROI | Romeoville | IL |
| USZH7 | Romeville | LA |
| USZYZ | Romney | IN |
| USOMD | Romoland | CA |
| USRQJ | Roebling | NJ |
| USRQB | Roebuck | SC |
| USREJ | Roeland Park | KS |
| USRFF | Roff | OK |
| USROG | Rogers | AR |
| USRGS | Rogers | CT |
| USRJM | Rogers | MN |
| USZQ2 | Rogers | OH |
| USRGQ | Rogers | TX |
| USRCY | Rogers City | MI |
| USRH2 | Rogers Haven | DE |
| USOEI | Rogersville | AL |
| USRVZ | Rogersville | MO |
| USRGV | Rogersville | TN |
| USRJQ | Roggen | CO |