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Mount Umunhum Summit and Back


Combine nature, amazing scenery, and interesting history while hiking to one of the highest peaks in the Santa Cruz Mts.

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Out and Back

3,474' 1,059 m


2,317' 706 m


1,195' 364 m


1,195' 364 m



Avg Grade (3°)


Max Grade (24°)

Dogs No Dogs

Features Birding · Views · Wildlife


Explore one of the highest peaks in the Santa Cruz Mountains. This excellent trail has it all. Hikers will enjoy nature with lots of different plants, amazing scenic views in all directions, and very interesting history.

Need to Know

About a third of the trail is exposed to the sun, so start early when the days are hot.
The Bald Mountain parking has limited parking, which is another reason to start early.
Download a free audio guide describing the natural environment, the scenery, and the rich history of the area on the Sierra Azul website.


This trail was opened to the public on September 18, 2017. The trail starts at the parking lot of Bald Mountain Trail.

It climbs steadily (1,200 ft) for 3.7 miles to the summit of Mount Umunhum, one of the highest peaks in the Santa Cruz Mountains. The trail is excellent and easy to follow, making its way up lots of switchbacks to ease the climb.

The trail goes through a variety of trees such as oak, madrone, manzanita etc. 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.

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.


Shared By:

Shlomo Waser

Trail Ratings

  4.4 from 16 votes


  4.4 from 16 votes
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308 Views Last Month
10,722 Since Sep 28, 2017



Guadalupe Creek Overlook
Sep 28, 2017 near Almaden…, CA
Mt. Umunhum, 3,488 ft., as seen from the north
Sep 1, 2017 near Lexingt…, CA
Up ahead is Mt. Umunhum summit
Nov 11, 2017 near Almaden…, CA
Native American Ceremonial Circle on top of Mount Umunhum. A sacred place for thousands of years to Native Americans.
Sep 30, 2017 near Lexingt…, CA
Plaque near the top.
Oct 27, 2018 near Lexingt…, CA
Very clean resting/picnic area near the top.
Oct 27, 2018 near Lexingt…, CA



Current Trail Conditions

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May 10, 2020
Clare Kiesel
Dec 30, 2019
Jerome Catrouillet
8mi — 2h 42m
Nov 2, 2019
Herbie Voor
8mi — 2h 45m
Sep 21, 2019
Ian Miles
Sep 7, 2019
Astrid Harris
Aug 24, 2019
Manoj Dasaraju
Was easy and enjoyed the hike.. Got there early morning and we were the first ones.. better to go early as there was traffic on our way down.. 8.3mi — 4h 04m
Aug 10, 2019
Ben Gremillion
Trail is in good shape: mostly shady and dusty. They've reopened the south/southeast sides of the radar block, including the trail leading there. 8mi — 4h 00m
Jul 14, 2019
Madhav S
7.8mi — 3h 00m