| Code | Name | Region |
|---|---|---|
| USUZA | Stanley | NC |
| USS5Y | Stanley | ND |
| USEYZ | Stanley | NY |
| USSYJ | Stanley | VA |
| USNYL | Stanley | WI |
| USSZT | Stanleytown | VA |
| USSR9 | Stansbury Park | UT |
| USSTI | Stanton | CA |
| USS8D | Stanton | DE |
| USP4T | St. Petersburg | PA |
| USGB8 | Staatsburg | NY |
| USKSY | Stacy | MN |
| USTVX | Stacyville | IA |
| USJCU | Stafford | CT |
| USVSZ | Stafford | KS |
| USXTF | Stafford | NY |
| USSTD | Stafford | TX |
| USSTB | Stafford | VA |
| USSFC | Stafford Springs | CT |
| USV3R | Stain George | VT |
| USSZY | Staley | NC |
| USTAI | Stallings | NC |
| USXLX | Stamford | CT |
| USSDJ | Stamford | NY |
| USSTF | Stamford | TX |
| US7SF | Stamford | VT |
| US9SG | Stamping Ground | KY |
| USSTM | Stamps | AR |
| USTNB | Stanberry | MO |
| USSGP | Springlake | TX |
| USSP7 | Springport, Jackson | MI |
| USSP8 | Springtown | TX |
| USSG9 | Springvale | ME |
| USSW9 | Springview | NE |
| USSPL | Springville | AL |
| USSG8 | Springville | CA |
| USSG5 | Springville | IA |
| USIGL | Springville | NY |
| USXMN | Springville | TN |
| USSNU | Springville | UT |
| USXPG | Springville, Suffolk | NY |
| USYSP | Sproul | PA |
| USUHD | Spruce Head | ME |
| USS4P | Spruce Pine | AL |
| USSPU | Spruce Pine | NC |
| USSU5 | Spur | TX |
| USUEC | Spurger | TX |
| USSQT | Squaw Valley | CA |
| USS2M | St. Maries | ID |
| USSFY | Springfield | MA |