Sonora Pass was the oldest of the trans-Sierra emigrant trails to California and later became the route crossed by Highway 108, the second-highest highway crossing of the range at 9,626 feet. The Bartleson-Bidwell Party, traveling with mules, horses, and oxen, made the first crossing on October 18, 1841, but wagons did not attempt the route until 1852. “Grizzly” Adams took the trail over Sonora Pass in April, 1854, and reported that old axel trees and wheels lay on all sides as melancholy evidence of the previous season’s disasters. The present route, first projected in 1862, was finally completed as a toll road in 1865 by Mono, Tuolumne, and Stanislaus Counties because of the extreme cost. It was said that a six-horse team needed three weeks to make the round trip between Sonora and Bridgeport.