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Mount Umunhum Loop



13.9 mile 22.4 kilometer loop
50% Singletrack


Ascent: 2,408' 734 m
Descent: -2,423' -739 m
High: 3,459' 1,054 m
Low: 1,301' 397 m


Avg Grade: 7% (4°)
Max Grade: 35% (19°)


No Dogs
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Trail shared by Shlomo Waser

Ride through forest to explore one of the highest peaks in the Santa Cruz Mountains.

Shlomo Waser

Electric Mountain Bikes Unknown

Features -none-


This ride takes you through the Sierra Azul forest to the summit of Mount Umunhum where the views are stunning. This summit is one of the highest peaks in the Santa Cruz Mountains and also has very interesting history.

Need to Know

Get more info and download a free audio guide describing the natural environment, the scenery, and the rich history of the area:…


This loop ride starts at the east entrance of Sierra Azul Open Space Preserve (at the intersection of Hicks Road and Mount Umunhum Road).

Ride up Mount Umunhum Road (10-12% slope), and after 1.7 miles, there is a large display sign on the right side of the road. This is the trailhead for the singletrack Mount Umunhum Trail. (This trail was opened to the public on September 18, 2017.)

Ride through the forest for 3.5 miles with lots of hairpin switchbacks. The average slope is about 6%. The last 0.2 miles is open only to hikers. To reach the summit, ride for 0.2 miles on the paved road.

The views from the summit are great: Silicon Valley lies below you, and (on a clear day) one can see all the way to San Francisco, Monterey Bay, and the Pacific Ocean. There are great views of all the mountains in the area, including Mount Hamilton and Mount Diablo. There are a few interpretive signs along the trail and many more on the summit area.

After the summit visit, ride down the Mount Umunhum Trail for about 3.2 miles, where the doubletrack Barlow Road starts. Take this connector trail for 1.5 miles to Woods Trail. The last section of the Barlow is quite steep (more than 20%). Turn right on the doubletrack Woods Trail and ride it for 2.3 miles back to the starting point. This section of the Woods Trail is quite moderate with lots of shade.

History & Background

The summit of Mount Umunhum has an eight-story concrete tower that is visible from many places in the South Bay Area. That tower was once a base holding a radar dish operated by the US Air Force from 1957-1980. After the base closed, the land was bought by the Mid Peninsula Open Space District (Mid-Pen) to be used as an open space for the public. However, due to hazardous materials and other safety issues, it was not open to the public until September 18, 2017.

For over 30 years, Mid-Pen worked on returning the area to mostly its original natural environment. However, they kept the iconic 86-foot tower.

The mountain's name means Hummingbird in the Ohlone language.


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Sep 2, 2019
Joonas Lehtinen
Aug 9, 2019
David Beter
Jul 6, 2019
Timothy Heath
Jul 4, 2019
barrett england
barlow road sucks- steep climbs and loose gravel decents, the flies are hella annoying — 7h 30m
Jun 23, 2019
Radovan Bauer
May 5, 2019
Marshall Beck
May 4, 2019
Bruce bike
rode 1.5hr up
Apr 29, 2019
Maya St

Trail Ratings

  4.0 from 17 votes


  4.0 from 17 votes
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in California


457 Views Last Month
9,808 Since Oct 4, 2017



Mount Umunhum Trail in a cloud rolling over the mountain.
Jul 6, 2018 near Lexingt…, CA
Madrone trees along the Mount Umunhum Trail.
Oct 12, 2017 near Almaden…, CA
Bikers on Mount Umunhum Trail
Oct 12, 2017 near Lexingt…, CA
Mount Umunhhum's Airforce Radar Tower was in use 1957-1980. This iconic structure is visible from many places in the South Bay Area.
Oct 4, 2017 near Lexingt…, CA
Silicon Valley and the Diablo Range as seen from the the Mount Umunhum summit.
Oct 4, 2017 near Lexingt…, CA
Along the Mount Umunhum Trail.
Oct 12, 2017 near Almaden…, CA

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