| Code | Name | Region |
|---|---|---|
| USCO4 | Cool | CA |
| USCCZ | Cooleemee | NC |
| USYDG | Coolidge | AZ |
| USGCL | Coolidge | GA |
| USCRN | Coon Rapids | IA |
| USXEG | Coon Rapids | MN |
| USVYD | Coon Valley | WI |
| USC89 | Coontown | NJ |
| USXO2 | Cooper | TX |
| USCPW | Cooper City | FL |
| USCEI | Cooper Landing | AK |
| USJLA | Cooper Lodge | AK |
| USC5R | Cooper River Landing | SC |
| USCPU | Coopersburg | PA |
| USCW4 | Cooperstown | ND |
| USCOP | Cooperstown | NY |
| USZCP | Coopersville | MI |
| UST24 | Coopertown | TN |
| USCOB | Coos Bay | OR |
| USCTI | Contoocook | NH |
| USCEN | Convent | LA |
| USONV | Converse | LA |
| USVTX | Converse | TX |
| USOC4 | Convoy | OH |
| USADP | Conway | AR |
| USC9W | Conway | KS |
| USC8K | Conway | KY |
| USZB8 | Conway | MA |
| USOWY | Conway | MI |
| USC2Y | Conway | NC |
| USCWY | Conway | NH |
| USQ7I | Conway | PA |
| USACZ | Conway | SC |
| USCYR | Conyers | GA |
| USCY5 | Conyngham | PA |
| USQCX | Cook | MN |
| USUAU | Cookeville | TN |
| USKPS | Cooks Springs | AL |
| USKS9 | Cooksville | IL |
| USNMC | Conklin | MI |
| USNKL | Conklin | NY |
| USCZU | Conley | GA |
| US7CE | Conley | KY |
| USCDY | Conneaut | OH |
| USCV3 | Conneautville | PA |
| USXEB | Connell | WA |
| USCQP | Connellsville | PA |
| USC25 | Connelly Springs | NC |
| USCXU | Connellys Springs | NC |
| USCEV | Connersville | IN |