Tuolumne County, California was established on February 18, 1850 and named for the Native American term for the area (tribe unknown)! Tuolumne could mean many things, but most likely “Place of Many Stone Houses!” Its county seat is Sonora, and its fair is also held in Sonora! You might recognize the Mark Twain Cabin, Columbia State Historic Park, and parts of Yosemite National Park, which are located in this county!