Overview

Built in 1923, the O'Shaughnessy Dam in Yosemite floods the Hetch Hetchy Reservoir, supplying water and electricity to much of southern California. The dam is immense, a spectacular sight. Visitors will find a number of outdoor recreation opportunities here.

Location & Information

You can reach the dam by taking Highway 120, then turning onto Evergreen Road a mile west of the Big Oak Flat entrance station. From there you drive on Hetch Hetchy Road, 16 miles to the parking area above the dam.

Hetch Hetchy Road is open from June to September.

Contact information:
Yosemite National Park
PO Box 577
Yosemite National Park, CA 95389
209-372-1000

Activities

Besides the wonderful views of Wapama Falls and the blooming wildflowers, there are a number of other activities to add some adventure to your vacation in Yosemite.

• Hiking
  Whether a short walk or a longer hike is your preference, you’ll find it at O'Shaughnessy Dam. Walking across the dam provides you with some education into the history of the dam with interpretive signs. Hike to the base of Wapama Falls on a 5-mile out-and-back trail. You’ll pass two other waterfalls along the way. A longer hike of 13.4 miles roundtrip is the Rancheria Falls Trail, a moderate skill trail continuing past Wapama Falls and taking you to the beautiful Rancheria Falls.
• Fishing
  Discover some great fishing in the Hetch Hetchy Reservoir and in the Tuolumne River above the reservoir. You can fish all year round here. Catch brook, rainbow and brown trout on the reservoir from the shore.

Fun Facts

The dam is named after Michael M. O'Shaughnessy, the San Francisco engineer in charge of the construction of the dam and the plans on creating the Hetch Hetchy Reservoir.

To protect views of the valley, the power-generation facilities of the dam have been concealed.