| Code | Name | Region |
|---|---|---|
| US9CF | Colfax | IL |
| USCOF | Colfax | LA |
| USOFX | Colfax | NC |
| USYCX | Colfax | WA |
| US8CF | Colfax | WI |
| USGTD | Colgate | ND |
| USCEQ | College | AK |
| USGQC | College City | CA |
| USQCG | College Corner | OH |
| USCGG | College Grove | TN |
| USCPG | College Park | GA |
| USCGS | College Park | MD |
| USL5P | College Place | WA |
| USCPN | College Point | NY |
| USCLL | College Station | TX |
| USCGD | Collegedale | TN |
| USL55 | Collegeville | CA |
| USCQ4 | Collegeville | IN |
| USLGV | Collegeville | MN |
| USCDQ | Colden | NY |
| USCXF | Coldfoot | AK |
| US8CP | Coldspring | TX |
| USCQ8 | Coldwater | KS |
| USCWA | Coldwater | MI |
| USCWP | Coldwater | MS |
| USQIM | Coldwater | MS |
| USCOW | Coldwater | OH |
| US7MI | Cole Camp | MO |
| USCZ9 | Colebrook | CT |
| USCKO | Colebrook | NH |
| USCMA | Coleman | MI |
| USOLZ | Coleman | OK |
| USCOM | Coleman | TX |
| USOEM | Coleman | WI |
| USIXC | Colerain | NC |
| USOLR | Coleraine | MN |
| US7CO | Coles | IL |
| USCU6 | Colesburg | IA |
| USCE8 | Coleville | CA |
| USCJ2 | Cohasset | MA |
| USXEF | Cohasset | MN |
| USKKO | Cohocton | NY |
| USCOO | Cohoes | NY |
| USAAG | Cohutta | GA |
| USCOK | Cokato | MN |
| USYWW | Cokeville | WY |
| USOBR | Colbert | GA |
| USCOL | Colbert | WA |
| USCBK | Colby | KS |
| USC8Y | Colby | WI |