| Code | Name | Region |
|---|---|---|
| USSVO | Summitville | OH |
| USSXG | Sumner | GA |
| US5SU | Sumner | IA |
| USS8U | Sumner | ME |
| USSWV | Summersville | WV |
| USUMR | Summerton | SC |
| USZSE | Summerville | GA |
| USURV | Summerville | PA |
| USUZC | Summerville | SC |
| USUVT | Sullivan City | TX |
| USULX | Sully | IA |
| USSLP | Sulphur | LA |
| USLPU | Sulphur | OK |
| USUUS | Sulphur Springs | AR |
| USSLR | Sulphur Springs | TX |
| USULN | Sultan | WA |
| USULT | Sultana | CA |
| USACF | Sumas | WA |
| USASZ | Sumiton | AL |
| USSU4 | Summer Shade | KY |
| USURL | Summerdale | AL |
| USFSF | Summerfield | FL |
| USUME | Summerfield | NC |
| USKSF | Summerfield | TX |
| USSUH | Summerhill | PA |
| USUMD | Summerland | CA |
| USSK3 | Summerland Key | FL |
| USS3U | Summers | AR |
| USSU8 | Summerset | IA |
| USUGC | Sugar Creek | OH |
| USS2G | Sugar Grove | IL |
| USSGX | Sugar Grove | PA |
| USUGH | Sugar Hill | GA |
| US9SU | Sugar Hill | NH |
| USSGR | Sugar Land | TX |
| USUGL | Sugar Loaf | NY |
| USS9N | Sugar Run | PA |
| USUGA | Sugar Valley | GA |
| USZSU | Sugarcreek | OH |
| USTKB | Sugarland | MD |
| USSIX | Suisun City | CA |
| USSIL | Suitland | MD |
| USSUG | Sulligent | AL |
| USULI | Sullivan | IL |
| USSIV | Sullivan | IN |
| US9VA | Sullivan | ME |
| USXSV | Sullivan | MO |
| USULV | Sullivan | NH |
| USUVS | Sullivan | OH |
| USIRS | Sturgis | MI |