NOTE: It has been “crazy busy” this first full weekend (Sept 23/24), with full parking lots, and motorists being turned back. You may want to consider waiting a few weekends, trying a weekday afternoon, or leaving your car at the bottom of the hill! (~7 miles and 2200 vertical feet, each way)
Thanks to the efforts of the Midpeninsula Open Space District ( https://www.openspace.org/ ) and the taxpayers of the neighboring cities, it’s now possible to drive, bicycle, and hike to the top of Mt. Umunhum.
Thanks to the efforts of the Umunhum Conservancy ( https://umunhumconservancy.org/) there’s actually something to see at the top! The historic Concrete Cube, visible from many miles away, has been saved from Mid-Pen’s bulldozers. (The work is not yet done, though. The cube needs to be sealed, or protected, to prevent long-term deterioration.)
All of the other buildings of the former Almaden Air Force Station (682nd Radar Squadron) have been removed. Some history and old photos here: https://en.wikipedia.org/wiki/Almaden_Air_Force_Station
If you’re inclined to hike or bike up, you can park at the intersection of Hicks Road and Mt Umunhum Road, or park about half-way up at the Bald Mountain parking lot.
View from Hicks Road parking:
Bald Mountain parking:
From the bottom, you can hike or mountain bike: Woods Trail > Barlow Road > Mt Umunhum Trail. Driving halfway up, you can pick up the Mt Umunhum Trail just a bit up the road from the Bald Mountain parking lot. (Mid-Pen’s page, plus a map link here: https://www.openspace.org/mount-umunhum-sierra-azul )
In all three parking areas: Hicks Road, Bald Mountain, and the summit, there are vault toilets and no drinking water. (Intrepid hikers or cyclists could bring a water filter and filter from the new horse trough at the summit. )
Arriving at the top, there’s parking for about 30 cars, then 159 steps up to the main viewing area. (Disabled vehicle tag holders can drive all the way up, and bypass the 159 steps. A quick dropoff is also OK at the very top, without a disabled tag.)
Along the side of the cube, and a few other spots at the summit, I was impressed to see benches made from solid pieces of redwood:
The new Mt Umunhum Trail is quite well done, with many switchbacks, and an even grade. It’s 3.6 miles, in length, from just above the Bald Mountain parking lot:
GPX Track: https://www.strava.com/activities/1193883351
…and if you’ve read this far, and still have time on your hands, here is a bit of what the freshly paved road looks like, followed by a portion of the new hiking trail (I took it very slow. I don’t recommend the trail on a skinny-tire road bike!)