Welcoming Spring on Mount Umunhum


This past Monday, I opened up Google Maps and searched for patches of green. I was looking for a nearby hike (preferably to a summit) that had great views, would give me a good workout, and leave me enough time to get home and make dinner. As the morning sunshine quickly ticked away, I spotted the Sierra Azul Open Space Preserve, roughly an hour's drive south from Silicon Valley.

Clicking through the preserve's website, I discovered a 7.4 mile roundtrip, 1150-foot elevation gain hike to a mountaintop called Mount Umunhum. This jogged my memory: A new friend, Davina, had just mentioned Mount Umunhum to me a few days ago. It turns out the Mount Umunhum Trail and Mount Umunhum's summit opened to the public in September 2017. The trail was new!

Reading on, I learned that at 3,486 feet, Mount Umunhum is one of the highest peaks in the Santa Cruz Mountains. The newly restored summit overlooks the San Francisco Bay, Santa Clara Valley, the Diablo Range, and even a sliver of the Pacific Ocean. It's taller than Mount Tamalpais in Marin County (2,571 feet), but shorter than Mount Diablo, east of San Francisco (3,849 feet). The views looked spectacular and it fit my criteria: I was in.


Click the map for driving directions to the parking lot for the Mount Umunhum Trail.

Here are 10 things I loved about Mount Umunhum:

1. Free maps. Free, full-color topographic maps are available from the Bald Mountain parking lot (where you pick up the trail) and the Mount Umunhum Summit parking lot. Several interpretive signs along the Mount Umunhum Trail color the route with the mountain's history. 

Bald Mountain parking

2. Well-signed junctions. The dirt trail is wide enough for two people to walk side-by-side and is clearly signed at every junction. It just feels new while you're hiking it too: There are no ruts or eroded sections of the trail—just a flat, well-graded path. 


3. Half-mile markers. I loved gauging my progress along the markers and it was motivating having them spaced along the entire trail. They face both directions too, so you can clearly see them whether you're hiking up or down the mountain.

mile markers

4. Beautiful woodlands. Electric green grass sprouted beside the trail as it weaved in and out of the shady canopy. I was surprised at how much shade there was along the Mount Umunhum Trail—I thought the hike would be more exposed than it was. 


5. Bridges! Summit views aside, nothing gets me revved up than crossing a bridge on a hike. On the Mount Umunhum Trail, you've got three :)


6. Mountain views. Right from the Bald Mountain parking lot, you're treated to views of the Diablo Range and rolling green preserves. It just gets better from there, with views east toward Mount Hamilton and a barely visible Lick Observatory as you climb. At the summit, you've got a 360-degree view of the San Francisco Bay, Santa Clara Valley, Mount Tamalpais, Mount Diablo, and a sliver of the Pacific Ocean.

Mount Umunhum

7. Radar Tower. The eight-story concrete "cube" is fun to spot as you hike towards it. It's a radar tower that was part of the Almaden Air Force Station that operated from the summit from 1957-1980. The base was like its own community, complete with a swimming pool and two-lane bowling alley. This video from MidPen's website has neat first-person accounts of the military presence there, among other stories.

8. Mount Umunhum Summit Parking. If you prefer to visit the summit without hiking to it, you can. Just drive to the Mount Umunhum Summit lot and climb 159 steps to the summit. Stay for sunset, too; the area closes a half hour after it.


9. Sacred History. The Amah Mutsun lived on Mount Umunhum thousands of years ago, and consider Mount Umunhum a sacred place. A ceremonial circle was built as part of the restoration of Mount Umunhum to honor their history. The name "Umunhum" is an Ohlone word meaning "resting place of hummingbirds."

10. It's FREE! (Okay, except for the cost of gas and hiking snacks...) There are no fees to hike (or park) at Mount Umunhum. 


1. Leave plenty of time for driving. The road is narrow and windy leading up to the parking areas; plan a good 45 minutes to an hour to get there from Silicon Valley.

2. Bring water. There's no potable water on the trail or at the summit. 

3. ...but there are benches at the summit where you can take a breather. Bring a picnic and enjoy the view!

4. Gates leading to the parking areas open at 7:00 a.m. and close a half hour after sunset.

5. Parking is limited (maybe 20ish spaces) at the Bald Mountain lot, so you may want to get an early start on a sunny weekend.  

6. Expect mountain bikers and horseback riders, as the Mount Umunhum Trail is open to both. I encountered several friendly mountain bikers while I hiked. 

7. Leave your furry friend at home. According to MidPen, "Dogs are not allowed on the trail, summit, parking lots, or roads in the Mount Umunhum area (includes dogs in cars)."

8. There are vault toilets in the Bald Mountain parking lot (where you start the Mount Umunhum Trail) and in the Mount Umunhum Summit lot.

9. As of this post, ADA accessible parking near the radar tower is closed Monday-Friday, and last 0.2 miles of the Mount Umunhum Trail are closed to the public (you can still reach the summit via the stairs next to the Mount Umunhum Summit lot). Check the Sierra Azul Preserve website for the latest updates.