| Calais School Department, ME (District) |
| Calallen ISD, TX (District) |
| Calamus-Wheatland Comm School District, IA (District) |
| Calaveras County Office of Education, CA (District) |
| Calaveras ESA, CA (ISD) |
| Calaveras Unified, CA (District) |
| Calcasieu Parish, LA (District) |
| Calcasieu Parish, LA (ISD) |
| Caldwell, KS (District) |
| Caldwell County, TX (ISD) |
| Caldwell County, MO (ISD) |
| Caldwell County, NC (ISD) |
| Caldwell County, KY (Phantom) |
| Caldwell County Schools, KY (District) |
| Caldwell County Schools, NC (District) |
