The Collaborative Charter Services Organization's member schools serve the following counties in California:

Northern California:                                  

  • Sonoma 
  • Marin
  • Lake
  • Solano
  • Contra Costa
  • Napa 
  • Mendocino

Southern California:

  • Imperial
  • Kern
  • Los Angeles
  • Orange
  • Riverside
  • San Bernadino 
  • San Diego
  • Ventura