Sonoma County is a county in the U.S. state of California. As of the 2010 United States Census, its population was 483,878. Its county seat and largest city is Santa Rosa. It is to the north of Marin County and the south of Mendocino County. It is west of Napa County and Lake County.
Sonoma County comprises the Santa Rosa-Petaluma, CA Metropolitan Statistical Area, which is also included in the San Jose-San Francisco-Oakland, CA Combined Statistical Area. It is the northwesternmost county in the nine-county San Francisco Bay Area region.
Address 591 4th St, Santa Rosa 95401, United States
Coordinates 38°26'25.773" N -122°42'50.778" E