Mendocino County is a county located on the North Coast of the U.S. state of California. As of the 2020 census, the population was 91,601. The county seat is Ukiah. Mendocino County consists wholly of the Ukiah, CA Micropolitan Statistical Area for the purposes of the U.S. Census Bureau. It is located approximately equidistant from the San Francisco Bay Area and California/Oregon border, separated from the Sacramento Valley to the east by the California Coast Ranges.