Hiking Project Logo

blue Mount Umunhum Summit and Back

  4.6 ( 12 ) Favorite


8.3 mile 13.3 kilometer out and back


Ascent: 1,195' 364 m
Descent: -1,195' -364 m
High: 3,474' 1,059 m
Low: 2,317' 706 m


Avg Grade: 5% (3°)
Max Grade: 44% (24°)


No Dogs
Driving directions Take a virtual tour
Zoom in to see details
Map Key

Trail shared by Shlomo Waser

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

Shlomo Waser

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.

Hiked this trail?

We need help with the following missing trail information:

Flora & Fauna

Is something wrong? Let us know. Have photos to share? Help fellow hikers know what's here.


Rate This Featured Hike

Rate Quality

   Clear Rating

Rate Difficulty

Share This Hike

Check In


Jul 14, 2019
Madhav S
7.8mi — 3h 00m
Jul 14, 2019
Jeff C
To top
Jul 5, 2019
cahiker exp
Jun 18, 2019
Scott Campbell
May 19, 2019
Sergiy Cherepov
8mi — 3h 00m
Apr 9, 2019
Neal Audenaert
Mar 9, 2019
Rama Murthy
3h 10m
Mar 1, 2019
Luke Davis

Trail Ratings

  4.6 from 12 votes


  4.6 from 12 votes
5 Star
4 Star
3 Star
2 Star
1 Star
Featured Hike Rankings


in California


253 Views Last Month
8,294 Since Sep 28, 2017
Intermediate Intermediate



Hiking Project is part of the REI Co-op family,
where a life outdoors is a life well lived.

Shop REI Hiking