| Code | Name | Region |
|---|---|---|
| USS23 | Sidney | IA |
| USS7I | Sidney | KY |
| USIJY | Sidney | MI |
| USSDY | Sidney | MT |
| USSNY | Sidney | NE |
| USSXY | Sidney | NY |
| USSDN | Sidney | OH |
| USIDM | Sidon | MS |
| USIEB | Sierra Blanca | TX |
| USSIM | Sierra Madre | CA |
| USAZS | Sierra Vista | AZ |
| USSI7 | Sierra Vista | CA |
| US83W | Sigel | IL |
| USSII | Signal Hill | CA |
| USS3M | Signal Mountain | TN |
| USQGU | Sigourney | IA |
| USSU9 | Sigurd | UT |
| USSIK | Sikeston | MO |
| USSHV | Shreveport | LA |
| USSHU | Shrewsbury | MA |
| USEZY | Shrewsbury | NJ |
| USQSY | Shrewsbury | PA |
| USQZY | Shrewsbury | WV |
| USS5L | Shroon | NY |
| USSHK | Shrub Oak | NY |
| USSUB | Shubuta | MS |
| USHJB | Shullsburg | WI |
| USUWX | Shumway | IL |
| USSHG | Shungnak | AK |
| USHQK | Shuqualak | MS |
| USUY9 | Shutesbury | MA |
| USPS4 | Siberia | IN |
| USZSL | Sibley | IA |
| USS5B | Sibley | LA |
| USIBZ | Sibley | MO |
| USIYD | Sicily Island | LA |
| USSV5 | Sicklerville | NJ |
| USSD3 | Sidell | IL |
| USXLZ | Shoreham | NY |
| USSRH | Shoreham | VT |
| USSRI | Shoreline | WA |
| USSHB | Shoreview | MN |
| USSW3 | Shorewood | IL |
| USDO9 | Shorewood | MN |
| USSJV | Shorewood | OR |
| USS9W | Shorewood | WI |
| USXSY | Short Hills | NJ |
| USEOH | Shorter | AL |
| USTRV | Shorterville | AL |
| USSS8 | Shortsville | NY |