| Code | Name | Region |
|---|---|---|
| USUP8 | Upperco | MD |
| USUPV | Upperville | VA |
| USUPT | Upton | MA |
| USXUP | Upton | NY |
| USUWY | Upton | WY |
| USURN | Urania | LA |
| USURC | Urbana | IA |
| USURB | Urbana | IL |
| USIUA | Urbana | IN |
| USURO | Urbana | OH |
| USUCR | Urbancrest | OH |
| USUV9 | Unionville | PA |
| USBU8 | Unionville | TN |
| USUZP | Uniopolis | OH |
| USUHI | Unity | ME |
| USUWI | Unity | WI |
| USUVC | Universal City | CA |
| USKVY | Universal City | TX |
| USM6S | University | MO |
| USUVX | University City | MO |
| USUH3 | University Heights | OH |
| USUP2 | University Park | FL |
| USUPK | University Park | IL |
| USUK7 | University Park | PA |
| USUKK | University Park | TX |
| USUUP | University Place | WA |
| USCCB | Upland | CA |
| USUPL | Upland | IN |
| USUPP | Upolu Point | HI |
| USUPQ | Upper Arlington | OH |
| USYUP | Upper Brookville | NY |
| USUDP | Union Dale | PA |
| USYUG | Union Gap | WA |
| USA8L | Union Grove | AL |
| USXUG | Union Grove | NC |
| USUGR | Union Grove | WI |
| USUH7 | Union Hall | VA |
| USQUP | Union Point | GA |
| USUSC | Union South Carolina | SC |
| USUSP | Union Springs | AL |
| USUSN | Union Springs | NY |
| USUOI | Union, Franklin | MO |
| USUIO | Union, Monroe | WV |
| USXUI | Union, Neshaboa | MS |
| USUOD | Uniondale | NY |
| USUT2 | Uniontown | KY |
| USUOO | Uniontown | OH |
| USUTN | Uniontown | PA |
| US7UN | Unionville | CT |
| USU2V | Unionville | MI |