23 counties

In California, there are 6 appellate districts that are divided into different counties. Each district has its own court of appeals. The counties in each district are Santa Clara, Santa Cruz, Monterey, San Benito, Alameda, Contra Costa, Marin, Napa, San Francisco, San Mateo, Solano, Sonoma, Del Norte, Humboldt, Lake, Mendocino, Los Angeles, San Luis Obispo, Santa Barbara, Ventura, Alpine, Amador, Calaveras, Mono, San Joaquin, Butte, Colusa, El Dorado, Glenn, Lassen, Modoc, Nevada, Placer, Plumas, Sacramento, Shasta, Sierra, Siskiyou, Sutter, Tehama, Trinity, Yolo, Yuba, Inyo, Imperial, Orange, Riverside, San Bernardino, San Diego, Fresno, Kings, Madera, Mariposa, Merced, Stanislaus, Tulare, Tuolumne, and Kern.