Sonoma County is divided into 40 school districts for kindergarten through twelfth-grade (K-12) educational services. There are 31 elementary, 3 high school, and 6 unified districts. Unified districts operate both elementary and secondary schools for the students residing within their boundaries.
The county’s school districts vary in size, serving both rural and urban areas. The smallest district in the county, Kashia, is located in a rural area and has about eight students. The largest district, Santa Rosa City High, enrolls over 11,000 students in the county’s most populous city.
Enrollment in Sonoma County public schools grew rapidly during the 1990s, but has been decreasing since 2001. In recent years, the countywide drop in enrollment has accelerated due to declining birth rates, natural disasters, and the region's high cost of living.