Areas Served

Counties served by the Diagnostic Center, Northern California.

Map of Diagnostic Center Northern (DCN) Counties Served.

The three California Diagnostic Centers serve the 58 counties of California by regionExternal link opens in new window or tab. (North, Central, South). The Diagnostic Center, Northern (DCN) is located in Fremont, California and serves the following counties:

  • Del Norte, Siskiyou, Modoc, Humboldt, Trinity, Shasta, Lassen, Tehama, Plumas, Butte, Glenn, Mendocino, Lake, Colusa, Yuba, Nevada, Sierra, Sonoma, Sutter, Placer, El Dorado, Alpine, Sacramento, Yolo, Napa, Marin, Solano, San Francisco, Contra Costa, Alameda, San Mateo, Santa Cruz, Santa Clara, San Benito, Monterey