Hetch Hetchy Dam Climb Bike Climb - PJAMM Cycling

Hetch Hetchy Dam Climb


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Climb Summary

Cycling Hetch Hetchy, Yosemite National Park

Ride 6 miles gaining 1,332’ to elevation 5,126’ at 4.1% average grade.

Hetch Hetchy Road on the way to the reservoir

Visit our Yosemite National Park page.

This is a fairly mild climb in Northwestern Yosemite National Park.  The climb begins at the O'Shaughnessy Dam and ends a few miles north of the park’s only entrance that does not access Yosemite Valley - the road dead ends at the dam.   The steepest mile is just under 5% average grade so this road bike climb is more for the beauty of the Hetch Hetchy area than it’s difficulty.

View of John on the dam with Hetch Hetchy Reservoir in the background.

O'Shaughnessy Dam was constructed in 1934.

The climb begins at Hetch Hetchy Reservoir

We climb from the dam south, away and up from the dam.

Rustic scenes on the way to the climb.

This is the northernmost entrance to the park.

This is a dead end - you cannot access the full park on this road.

It’s about 7 ½ miles to the dam from the Ranger Kiosk

No fee to enter as of October, 2019.

Just past the ranger station

Start at not on the dam.

Just past the start of the climb - riding up the road from the reservoir.

View from the road about a mile up from the dam.

View about halfway up the climb.

That’s a wrap!!


Hetch Hetchy Valley was revered as a scenic equivalent to Yosemite Valley before the dam was built.

Photo:  sfchronicle.com

San Francisco began efforts to dam the Toulomne River at the western end of the Hetch Hetch Valley in the early 19th Century.  Of course, the project was opposed by environmentalist and naturalists who respected and appreciated the delicate beauty of this unique and spectacular area.


June 25, 1913 SF Chronicle article.

Photo:  sfchronicle.com 

The 1906 earthquake and fire exposed San Francisco’s inadequate water supply and led to efforts to tap the Toulomne River as the primary water source for that city.  This led to a 7 year environmental battle with John Muir and the Sierra Club.   In 1913 Congress passed the Raker Act which permitted a damn to be constructed in Yosemite National Park’s Hetch Hetchy Valley.  Construction of the dam began in 1914 and was completed 20 years later in 1934.  Hetch Hetchy Reservoir provides water for 80% of the City and County of San Francisco.  

Moccasin is a company town owned almost entirely by the City and County of San Francisco

Moccasin is occupied by employees who work for the Hetch Hetchy Water & Power System.