Sonoma is the southwestern county of California's Wine Country region, which also includes Napa, Mendocino, and Lake counties. It has thirteen approved American Viticultural Areas and over 250 wineries. In 2002 Sonoma County ranked as the thirty-second county in the United States in agricultural production. As early as 1920 Sonoma County was ranked as the eighth most agriculturally productive U.S county and a leading producer of poultry products, hops, grapes, prunes, apples, and dairy products, largely due to the abundance of high quality irrigation water. More than 7.4 million tourists visit each year, spending more than $1 billion in 2006. Sonoma County is the home of Sonoma State University and Santa Rosa Junior College.
Sonoma County was once home to several Native American tribes, who lived within the carrying capacity of the land; by 1850, European settlement had set a new direction that would prove to radically alter the course of land use and resource management of this region. As of 2007, Sonoma County has rich agricultural land, albeit now largely divided between two nearly monocultural uses: grapes and pasturage. The voters have twice approved open space initiatives that have provided funding for public acquisition of natural areas, preserving forested areas, coastal habitat, and other open space.