AAA Editor Notes
Hetch Hetchy Reservoir is accessed from SR 120, just w. of the Big Oak Flat entrance; visitors can follow Evergreen Rd. to re-enter the park at Hetch Hetchy. The 38-mile drive from the valley can be covered easily in 2 hours. A paved road leads 7 miles from Mather to the 312-foot dam, which impounds San Francisco's water supply.
Before the dam was built in the 1920s, the Hetch Hetchy Valley rivaled Yosemite Valley in beauty. The Hetch Hetchy Valley floor is now under 300 feet of water.
You should carry tire chains in the fall, winter and spring.