Stand on the O'Shaughnessy Dam and ask yourself, where does my drinking water come from? This reservoir currently supplies drinking water to 2.7 million San Francisco Bay Area residents.

After parking your vehicle, take a short walk to the O'Shaughnessy Dam to get views of the reservoir and two waterfalls, Tueeulala Fall and Wapama Fall.

The O'Shaughnessy Dam (named for the chief engineer) was completed in 1938. Today, this 117-billion-gallon reservoir supplies pristine drinking water to 2.7 million Bay Area residents and industrial users. It also supplies hydro-electric power generated by two plants downstream. The reservoir is eight miles long and the largest single body of water in Yosemite.

Hours

Unlike other areas of Yosemite, the road to Hetch Hetchy is open only during daylight hours, from sunrise to sunset. 

From November through March, the Hetch Hetchy Road may be subject to closures or chain requirements due to ice and snow. Call 209/372-0200 (1,1) for current road conditions.

Getting Here

Located on the Hetch Hetchy Road, which becomes a one-way loop road, eventually leading to the O'Shaughnessy Dam parking area.

Rules & Regulations

• Sleeping in your car or RV overnight in a parking lot or along the side of the road is not allowed.
• You may store food inside your car (out of sight, with windows completely closed) only during daylight hours. Empty your car of all food, drinks, coolers, toiletries, and trash after dark. Even an empty candy bar wrapper is enough temptation to entice a bear to break into your car. Vehicles containing food after dark may be impounded and/or cited.
• Swimming and boating are prohibited in Hetch Hetchy Reservoir in order to maintain a clean source of drinking water.
• Dogs and other pets are prohibited on all trails and on the dam. Wild animals are threatened by domestic animals in their territory and may endanger your pets. Dogs are allowed in the parking area but must be leashed at all times.
• Fishing is allowed year-round in the Hetch Hetchy Reservoir. A valid California fishing license is required. Daily bag limit for the Hetch Hetchy reservoir is five per day and ten in possession.

Accessibility

Designated accessible parking spaces are available.