Page Type Page Type: Mountain/Rock
Location Lat/Lon: 37.16060°N / 121.897°W
Additional Information County: Santa Clara
Activities Activities: Hiking
Seasons Season: Spring, Summer, Fall, Winter
Additional Information Elevation: 3486 ft / 1063 m
Sign the Climber's Log


As of September 18, 2017, after decades of inaccessibility, Mount Umunhum has finally become open to the public. The status of Mount Umunhum has changed many times since the creation of this page, so many photos here will reflect what the summit used to be, and will remain attached to this page for historical reference. My hope is that with the opening of the mountain, new photos will be posted by other contributors. 


682nd radar squadron patch
AAFS Patch

Mt. Umunhum (which roughly translates to "Hummingbird" in Ohlone Indian; pronounced Uhhh-mun-uhm) is a major landmark in the Southern Bay Area and a truly unique peak. A mere three feet higher than its neighbor Mount Thayer*, most people recognize it from the huge "box-like structure" that stands on its summit, clearly visible from all around the South Bay. The structure is known by several monikers such as "The Monolith", "The Cube", and "The Radar Tower", yet is mostly known simply as "The Box". The Box is an 84.5 foot tall foundation remnant of an AN/FPS-24 U.S. Air Force radar tower. Between 1957 and 1980, the infamous Almaden Air Force Station, which occupied the summit area, maintained many radar and transmitting equipment as lookout for Soviet attack planes coming in over the Pacific. The Box at one point had a large radar dish on top of it until the closure of the station. Such bulky radar equipment quickly became outdated and replaced with newer radar technologies, and in the early 1980s the Air Force decommissioned the station and left everything atop the mountain abandoned. They left behind not just a radar station, but an entire town. The summit and surrounding slopes of Mount Umunhum were quite isolated from San Jose, so the station needed something of a self sustaining populace. During the operating years of the station, the "town" boasted amenities such as residential buildings, a recreation center with swimming pool, a banquet hall, a commissary, and even a bowling alley. 

Because the Almaden Air Force Station was built in a time where regard for environmental and human health was a bit stalled, the structures contained a fair amount of lead paint and asbestos. From the early 80s all the way into the early 2010s, the summit structures sat, slowly decaying and falling into disrepair. Even though the land on which the station sat on was Mid Peninsula Open Space land, public access to the mountain was strictly prohibited. All road accesses to the summit crossed heavily guarded private property owned by very isolated and sometimes violent individuals. Any non-road approach to the summit involved a tedious bushwhack through steep, thick, poison oak covered slopes, with the added danger of Mexican Cartel-run clandestine backcountry marijuana grow operations. Because of Mount Umunhum's isolated, foreboding nature (as well as the eerie presence of the summit Box), it generated quite a bit of inspiration for local urban legends (see below section). For many years, the only way to visit Mt. Umunhum was to trespass. During the off limits years, the mountain could have been considered class S10 on the "Sneak Peak Climbing" scale.
*The elevations surveyed by the USGS for Mount Umunhum and Mount Thayer were 3,486 feet and 3,483 feet, respectively. The cleanup and preservation of the mountain tops involved resurfacing and reforming the summits from bulldozed lots to more natural landscapes, and in doing so, heightened both summits by some amount. The verdict is still out on the new elevations, so until USGS provides updated elevations, I will list the elevations of these mountains by their old measurements. Mount Thayer may be even taller than Mount Umunhum!
The  box  and summit of Mt....
The Summit from McQueen Ridge
These two photos show the difference between the pre and post cleanup of the summit structures. The top photo was taken in 2005 and the bottom photo in 2017. 


New Improved Box
Summit post cleanup and opening (2017)
Luckily in the early 2010s, the open space district received a federal grant to clean the summit, restore native plant life, and open the summit to the public, complete with visitor facilities. Over a period of several years, all structures (besides the Box) were completely torn down and the summit and surrounding slopes were restored to match more of the natural environment. The road to opening was not an easy one, as the project suffered delays and design disagreements, most notably regarding what to do with the 5 story summit Box. After much back and forth, the Box was deemed a Santa Clara County Historical Landmark, and it was decided that the Box would remain intact and standing on the summit. Informative plaques were installed, new trails were built, parking lots enlarged, and roads were re-surfaced. What was once a strictly inaccessible, decrepit, and yet somewhat wild place has now been changed into a place of legal recreation and access, the way that mountains should be, free for anybody to enjoy who is inclined to do so. Mount Umunhum is in many ways a symbol of the South Bay, and to have such a resource within spitting distance of Silicon Valley is very special.
Mount Umunhum's summit can be reached via the Mount Umunhum Trail, a 3.4 mile (one way) multi-use trail, or by vehicular access via Mount Umunhum Road.



Mount Umunhum
Mt Umunhum in the 70s.

Getting There

A Mighty Peak
Mt. Um from Mt. Um Road.
In order to get to Mt. Umunhum, you must first find Mt. Umunhum Road. From Camden Ave. in San Jose, turn west onto Hicks Road. Go past Shannon Road and Guadalupe Reservoir. After some elevation gain, you'll come to a rest area at a 4-way intersection and Mt. Umunhum Road to the right. Travel up Mount Umunhum Road 1.6 miles to the Bald Mountain Trailhead, where there is a large parking lot. Park here for access to the Mt. Umunhum Trail (well signed and marked), or alternatively, drive all the way up to the large parking lot just beneath the summit and walk the 150 or so steps to the top. 

    Red Tape

    Mount Umunhum is only open from 7am to half hour past sunset. There are gates that automatically close when it gets dark. Camping is not allowed, and there are no usage fees. The below photo is the first of many signs that would greet would-be peakbaggers before the mountain was opened, at the infamous "Line of Death". 

    When To Climb

    Anytime. Summer temperatures can get into the 100's. Winter can bring snow, but no more than a few inches. The summit can get quite windy, and 50+ mph gusts aren't uncommon.
    Mt. Umunhum Mt. Umunhum looms over south San Jose at dusk.
    Summit B&W

    What's Up With Them White Albinos? -Rumors and Stories

    There were many weird stories and rumors that pertained to Mt. Umunhum when it was off limits. Most of these rumors were of false nature, but some were partly true. This section contains a bit of Mt Umunhum history, myths and legends written way back during the initial creation of the page, - I have left them written as they were.  One rumor says that Almaden Air Force Station is still in operation. I don't know where this came from, but if you see the place today, it doesn't take a rocket scientist to know that the place is very much abandoned. There are also stories of marijuana plantations around Mt. Umunhum. This is true. In August of 2005, a raid was done on a marijuana farm on the north western slope of El Sombroso, not far from Mt. Umunhum, that left one grower dead. On July 24, 2006, there was another raid closer to Mt. Umunhum in the Herbert Creek drainage, south of Mt. Umunhum Road. On July 10, 2007, the DEA eradicated even more pot plants in that same creek drainage. This is something to take into consideration when hiking Mt. Umunhum. I have no doubt that more marijuana farms linger in the hillside somewhere, and the growers obviously don't want anybody in there. It's best sticking to main routes to keep from accidentally stepping onto one. Another rumor is that the people who live around Mt. Umunhum carry guns and will fire at you. This has never happened to me, but countless people all over the net claim that they have been threatened with firearms. I have found bullet shells on the road near the summit, so this is something to think about. This rumor is a pretty weird one, and I have my doubts about it: somewhere around Mt. Umunhum, there is a enclave of hostile albinos that will kidnap you if you venture into their territory. This sounds like the stuff of legend. A while ago, I crossed paths with a land owner at gate SA-08 (not on private property) who mentioned to me something about "white albinos". I was also talking to a ranger for the Mid-peninsula Open Space District, and he said that there were some hard-core naturalist type of people living on the slopes of Mt. Umunhum. I don't know if he was serious or not, but it is an interesting idea I guess. Nevertheless, as it turns out, the "White Albino" rumor has circulated all around the Santa Cruz Mountains for many years. There has also been numerous reports of albinos living in Alum Rock Rock Park in the East Foothills. So, chances of there being crazy, hostile, cannibalistic white albinos near Mt. Umunhum are low...but one can never be too careful. The talk of albinos certainly is the most mysterious thing that surrounds the mountain, as well as the area. People talk of an "albino farm", which I believe is the trailer park off of Mt. Umunhum Road just before the "line of death". Another possible location for this alleged albino farm could be in the small Swedish retreat of Sveadal, a bit southeast of Umunhum. No albinos live at either location, as far as I know. I have heard stories of people on Hicks Road who inform the teens looking for albinos that "there is only one albino who lives up here, and he wants to be left alone." So, the legend is still open for debate.



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Children refers to the set of objects that logically fall under a given object. For example, the Aconcagua mountain page is a child of the 'Aconcagua Group' and the 'Seven Summits.' The Aconcagua mountain itself has many routes, photos, and trip reports as children.