| Code | Name | Region |
|---|---|---|
| USRFW | River Falls | WI |
| USRVO | River Forest | IL |
| USRG6 | River Grove | IL |
| USRIG | River Grove/chicago | IL |
| USR4V | River Hills | WI |
| USRGN | Ringtown | PA |
| USRIO | Ringwood | IL |
| USRIJ | Ringwood | NJ |
| USR3W | Ringwood | OK |
| USR88 | Rio | WI |
| USRB8 | Rio Blanco | CO |
| USDJL | Rio Dell | CA |
| USRGF | Rio Grande | NJ |
| USRE4 | Rio Grande | OH |
| USRGC | Rio Grande City | TX |
| USRH8 | Rio Hondo | TX |
| USRLI | Rio Linda | CA |
| USRO6 | Rio Oso | CA |
| USRRC | Rio Rancho | NM |
| USRRQ | Rio Rico | AZ |
| USRVA | Rio Vista | CA |
| USIAJ | Riparius | NY |
| USRPP | Ripley | CA |
| USRPM | Ripley | MS |
| USRP5 | Ripley | NY |
| USRQF | Rifton | NY |
| USIG8 | Riga | MI |
| USRG3 | Rigby | ID |
| USRG7 | Riggins | ID |
| USIEY | Riley | KS |
| USR33 | Riley | MI |
| USRI9 | Rillito | AZ |
| USRIM | Rimer | OH |
| USRB3 | Rimersburg | PA |
| USRIK | Rincon | GA |
| USNJN | Rincon | NM |
| US9RI | Rindge | NH |
| USR2R | Riner | VA |
| USRGD | Ringgold | GA |
| USRJO | Ringgold | PA |
| USRXV | Ringgold | VA |
| USRAF | Ringle | WI |
| USYGO | Ringoes | NJ |
| USR3G | Ringold | OK |
| USGSD | Ringsted | IA |
| USRGZ | Ridgely | MD |
| USRVQ | Ridgeville | IN |
| USRIS | Ridgeville | SC |
| USDLC | Ridgeville Corners | OH |
| USXRY | Ridgeway | CO |