O'Shaughnessy Dam, Gravity dam in Tuolumne County, United States
The O'Shaughnessy Dam rises 430 feet high across the Tuolumne River, forming the Hetch Hetchy Reservoir within Yosemite National Park.
Construction of the dam began in 1919 and concluded in 1923, with additional height modifications completed between 1935 and 1938.
The dam's construction sparked environmental debates that continue today, marking a turning point in American conservation and water management priorities.
The reservoir supplies drinking water to 2.5 million San Francisco Bay Area residents and generates hydroelectric power through two downstream plants.
The Hetch Hetchy system produces water of such high quality that it requires only primary filtration due to strict watershed protection measures.
Location: Tuolumne County
GPS coordinates: 37.94750,-119.78833
Latest update: May 27, 2025 13:18
Hetch Hetchy
122 m
Emigrant Wilderness
21.9 km
Hetch Hetchy Reservoir
3.4 km
Ribbon Fall
26.6 km
Cherry Lake
11.8 km
Wapama Falls
2.9 km
Grand Canyon of the Tuolumne
16.6 km
Lake Eleanor
8.7 km
Crane Flat Campground
22.2 km
Mount Hoffmann
26.9 km
Eagle Peak
27.1 km
Tueeulala Falls
2.3 km
Yosemite Creek Campground
21.6 km
Crane Flat Fire Lookout
21.1 km
Tamarack Flat Campground
22.2 km
Hetch Hetchy to Lake Vernon Trail
8.6 km
Quaking Aspen Falls
22.1 km
Merced Grove Ranger Station
22.6 km
Frog Creek Cabin
6.3 km
Yosemite Wilderness
16.4 km
Dead Giant Tunnel Tree
20 km
Crane Flat
21.1 km
Tamarack Flat
22.3 km
South Fork Tuolumne River Bridge
18.2 km
Rim of the World Vista
26.1 km
South Fork Tuolumne River Bridge
24.1 km
Wildcat Creek Bridge
25.5 km
Cascade Creek Bridge
25.3 kmReviews
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