Sonoma County is on the northwest coast of California, part of the greater San Francisco Bay Area. Its largest city and county seat is Santa Rosa.
In 2002 Sonoma County ranked as the second county in the United States in agricultural production. As of 2007, Sonoma County has rich agricultural land, albeit now largely divided between two monocultural uses: grapes and pasturage. The County has a total area of 1,768 mi², 89% is land, and 11% is water. At the 2000 census, there were 458,614 people, 172,403 households, and 112,406 families in Sonoma County.