| Code | Name | Region |
|---|---|---|
| USSUS | Spirit Of Saint Louis Apt/saint Louis | MO |
| USSZ3 | Spiritwood | ND |
| USSD8 | Splendora | TX |
| USPFZ | Spofford | NH |
| USGEG | Spokane | WA |
| USPKV | Spokane Valley | WA |
| USSPO | Spooner | WI |
| USSAW | Spotswood | NJ |
| USXXO | Spotsylvania | VA |
| USSPF | Spearfish | SD |
| USOPM | Spearman | TX |
| USKRI | Spearville | KS |
| USQSP | Speed | IN |
| USS8W | Speedway | IN |
| US7BA | Speedwell | TN |
| US9SL | Spelter | WV |
| USSNX | Spenard | AK |
| USSPW | Spencer | IA |
| USRWQ | Spencer | IN |
| USSPR | Spencer | MA |
| USECR | Spencer | NC |
| USSPC | Spencer | NY |
| USSPP | Spencer | OH |
| USQXC | Spencer | TN |
| USSC8 | Spencer | VA |
| USSNZ | Spencer | WI |
| USWVP | Spencer | WV |
| USSP6 | Spencerport | NY |
| USS9P | Spencerville | IN |
| USSFU | Spanish Fork | UT |
| USIFO | Spanish Fort | AL |
| USZUS | Spanish Springs | NV |
| USSPM | Sparks | GA |
| USSRM | Sparks | MD |
| USKP3 | Sparks | NE |
| USSPK | Sparks | NV |
| USFKG | Sparks Glencoe | MD |
| USSVW | Sparrevohn | AK |
| USPWU | Sparrow Bush | NY |
| USPPO | Sparrows Point | MD |
| USAA5 | Sparta | GA |
| USSAR | Sparta | IL |
| USSQH | Sparta | MI |
| USZSR | Sparta | NC |
| USSZA | Sparta | NJ |
| USSPX | Sparta | TN |
| USCMY | Sparta | WI |
| USSPA | Spartanburg | SC |
| USSPB | Spartansburg | PA |
| USSFJ | Southfield | MI |