| Code | Name | Region |
|---|---|---|
| USCN7 | Cornelius | NC |
| USCZG | Cornelius | OR |
| USCZH | Cornelius Pass | OR |
| USCBA | Corner Bay | AK |
| USCN8 | Cornersville | TN |
| USCGC | Corning | AR |
| USCJG | Corning | CA |
| USADB | Corning | IA |
| USOIG | Corning | NY |
| USC9P | Copperton | UT |
| USOQL | Coquille | OR |
| USCGB | Coral Gables | FL |
| USCPJ | Coral Springs | FL |
| USCWV | Coral Way Village/miami | FL |
| USCVB | Coralville | IA |
| USUFF | Coram | NY |
| USCPP | Coraopolis | PA |
| USCBI | Corbin | KY |
| USIOY | Corbin City | NJ |
| USCRO | Corcoran | CA |
| USCO8 | Corcoran | MN |
| USADF | Cordele | GA |
| USLJA | Cordelia | CA |
| USCDV | Cordova | AK |
| US299 | Cordova | AL |
| USODV | Cordova | IL |
| USCD7 | Cordova | MD |
| USOYV | Cordova | NC |
| USDOA | Cordova | TN |
| USOOZ | Coosa | GA |
| USOOP | Coosa Pines | AL |
| USKOP | Copake | NY |
| USOPE | Copake Falls | NY |
| USOPB | Copan | OK |
| USOPU | Cope | CO |
| USDZC | Cope | SC |
| USC3O | Copell | TX |
| US2FL | Copemish | MI |
| USKOG | Copenhagen | NY |
| USCET | Copiague | NY |
| USQCV | Coplay | PA |
| USCPY | Copley | OH |
| USCEJ | Coppell | TX |
| USCO9 | Copper Canyon | TX |
| USCZC | Copper Centre | AK |
| USQCE | Copper Mountain | CO |
| USTGC | Copperas Cove | TX |
| USCPI | Copperhill | TN |
| US6OP | Copperopolis | CA |
| USCK3 | Cooksville | MD |