Tuolumne County (/tuˈɒləmi/), officially the County of Tuolumne, is a county in the U.S. state of California. As of the 2020 census, the population was 55,620.[1] The county seat and only incorporated city is Sonora.[2] The county is in the Sierra Nevada region.
The northern half of Yosemite National Park is in the eastern part of this county.
Tuolumne County was founded in 1850.