| Code | Name | Region |
|---|---|---|
| USCO2 | Crab Orchard | TN |
| USCO5 | Crab Orchard | WV |
| USC3T | Crabtree | NC |
| USZRA | Crabtree | PA |
| USCFQ | Crafton | PA |
| US7CF | Craftsbury | VT |
| USC6R | Cragford | AL |
| USCGA | Craig | AK |
| USCIG | Craig | CO |
| USA7T | Craig | MO |
| USR9M | Craigmont | ID |
| USGZG | Craigsville | WV |
| USZRC | Cramerton | NC |
| USC9I | Cranberry Isles | ME |
| USCPD | Cranberry Lake | NY |
| USRYT | Cranberry Township | PA |
| USCQE | Cranbury | NJ |
| USKR7 | Crandall | GA |
| USKRA | Crandall | TX |
| USRWZ | Crandon | WI |
| USCVK | Covington | KY |
| USCWT | Covington | LA |
| USOVI | Covington | OH |
| USVNG | Covington | PA |
| USAAH | Covington | TN |
| USCVJ | Covington | VA |
| USVGB | Covington | WA |
| USIWP | Covington Township | PA |
| USZWN | Cowan | TN |
| USPA6 | Cowansville | PA |
| USZJH | Coward | SC |
| USCW2 | Cowen, Webster | WV |
| USYHE | Cowiche | WA |
| USC7W | Cowlesville | NY |
| USCPQ | Cowpens | SC |
| USC2C | Coxs Creek | KY |
| USCS6 | Coxsackie, Greene | NY |
| USC9Y | Coyanosa | TX |
| US3CY | Coyote | NM |
| USQCZ | Cozad | NE |
| USOPD | Coupland | TX |
| USOUT | Courtdale | PA |
| USC6Y | Courtenay | ND |
| USCBP | Courtland | AL |
| USURD | Courtland | CA |
| USCBQ | Courtland | KS |
| USCBR | Courtland | MN |
| USVXQ | Courtland | VA |
| USCH7 | Coushatta | LA |
| USCV7 | Cove | AR |