| Code | Name | Region |
|---|---|---|
| USP3N | Chappaqua | NY |
| USCDO | Chardon | OH |
| USCIQ | Chariton | IA |
| US3MT | Charlemont | MA |
| USZOI | Charleroi | PA |
| USCCY | Charles City | IA |
| USZZY | Charles City | VA |
| USCTS | Charles Town | WV |
| USC9B | Chambersville | PA |
| USCMM | Chamblee | GA |
| USCMI | Champaign | IL |
| USFNP | Champion | MI |
| USCJM | Champion | PA |
| USHZG | Champions Gate | FL |
| USCHM | Champlain | NY |
| USAP9 | Champlain | VA |
| USNMH | Champlin | MN |
| USWCR | Chandalar | AK |
| USCHD | Chandler | AZ |
| USCJL | Chandler | IN |
| USZ8R | Chandler | MN |
| USDFH | Chandler | OK |
| USC9V | Chandlersville | OH |
| US5CH | Chandlerville | IL |
| USCHQ | Chanhassen | MN |
| USCHH | Channahon | IL |
| USCVU | Channelview | TX |
| USNZG | Channing | MI |
| USCHB | Chadbourn | NC |
| USCFR | Chadds Ford | PA |
| USCDR | Chadron | NE |
| US8CW | Chadwick | IL |
| USZZD | Chadwicks | NY |
| USCQ9 | Chaffee | MO |
| USFFC | Chaffee | NY |
| USCFO | Chagrin Falls | OH |
| USJCO | Chalco | NE |
| USCHF | Chalfont | PA |
| USCIK | Chalkyitsik | AK |
| USGXM | Challenge | CA |
| USCHL | Challis | ID |
| US7BE | Chalmers | IN |
| USCLQ | Chalmette | LA |
| USQHM | Chama | NM |
| USVHB | Chamberino | NM |
| USCH9 | Chamberlain | SD |
| USM9B | Chambers | AZ |
| USCBB | Chambersburg | PA |
| USENL | Centralia | IL |
| USRXC | Centralia | KS |