| Code | Name | Region |
|---|---|---|
| USQRY | Surry | VA |
| USSVE | Susanville | CA |
| USUIT | Susitna | AK |
| USSH7 | Susquehanna | PA |
| USUEX | Sussex | NJ |
| USSSY | Sussex | WI |
| USSV6 | Sutersville | PA |
| USUEN | Sutherland | NE |
| USZSD | Sutherland | VA |
| USSLD | Sutherlin | OR |
| USUNR | Sunray | TX |
| USXUN | Sunrise | FL |
| USZZZ | Sunrise Beach | MO |
| USSNC | Sunset | CA |
| USSU6 | Sunset | LA |
| USSS4 | Sunset | UT |
| USSBE | Sunset Beach | CA |
| USS99 | Sunset Beach | NC |
| USUEA | Sunset Hills | MO |
| USS8L | Sunset Valley | TX |
| USSWE | Sunset Whitney Ranch | CA |
| USSHA | Sunshine | AL |
| US9SH | Sunshine | LA |
| USAZ3 | Superior | AZ |
| US9OQ | Superior | CO |
| USUPR | Superior | NE |
| USSUW | Superior | WI |
| USST8 | Superior Township | MI |
| USLQF | Supply Brunswick County | NC |
| USSYX | Supreme | LA |
| USSRJ | Sunbury | PA |
| USSKQ | Suncook | NH |
| USSD5 | Sundance | UT |
| USSUC | Sundance | WY |
| US5SR | Sunderland | MA |
| USV87 | Sunderland | VT |
| USS5E | Sunfield | MI |
| USJWR | Sunflower | MS |
| USSND | Sunland | CA |
| USXSP | Sunland Park | NM |
| USSM3 | Sunman | IN |
| USXSU | Sunny Isles | FL |
| USSUT | Sunny Point | NC |
| USYUY | Sunny Side | GA |
| USSUY | Sunnyside | WA |
| USSS6 | Sunnyside, Queens | NY |
| USUNP | Sunnyslope | ID |
| USSNN | Sunnyvale | CA |
| USSVD | Sunnyvale | TX |
| USUOL | Sunol | CA |