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Mt. Umunhum Out-and-Back

Intermediate
 4.6 (5) RECOMMENDED ROUTE

Rolling and winding trail from mid-mountain to the radar station with some sharp switchbacks at the top.


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Map Key

8.0

Miles

12.8

KM

85%

Singletrack

3,460' 1,055 m

High

2,299' 701 m

Low

1,178' 359 m

Up

1,176' 359 m

Down

6%

Avg Grade (3°)

17%

Max Grade (10°)

Dogs Unknown

E-Bikes Unknown

Features -none-

Overview

Starts across the road from the Sierra Azul Open Space Preserve parking lot, a little less than half way up Mt. Umunhum Road from Hicks Road, and returns the same way.

Need to Know

Lots of hikers on the weekend so be careful, especially on the descent. There are restrooms near the top. The last 1/8 mile from the parking lot to the top is on the paved road (or steps).

Description

The trail is winding and rolling enough to distract somewhat from the vertical climb. You can see beautiful vistas and the iconic radar station building at the top getting closer and closer at many points throughout the ride.

The surface is mostly smooth, with enough room to (carefully) pass hikers and other bikers. There is a series of very sharp switchbacks near the top, and spectacular views in all directions at the top. The 8-story radar building itself is off-limits and is fenced off, but there are restrooms, shade structures, and lookout points nearby.

Shared By:

Tom Rusnock

Trail Ratings

  4.6 from 5 votes

#1529

Overall
  4.6 from 5 votes
5 Star
60%
4 Star
40%
3 Star
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2 Star
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1 Star
0%
Recommended Route Rankings

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2,226 Since Mar 31, 2019
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Photos

Mount Umunhum Trail in a cloud rolling over the mountain.
Jul 6, 2018 near Lexingt…, CA
Madrone trees along the Mount Umunhum Trail.
Oct 12, 2017 near Almaden…, CA
Bikers on Mount Umunhum Trail
Oct 12, 2017 near Lexingt…, CA
Mount Umunhhum's Airforce Radar Tower was in use 1957-1980. This iconic structure is visible from many places in the South Bay Area.
Oct 4, 2017 near Lexingt…, CA
Silicon Valley and the Diablo Range as seen from the the Mount Umunhum summit.
Oct 4, 2017 near Lexingt…, CA
Along the Mount Umunhum Trail.
Oct 12, 2017 near Almaden…, CA

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Check-Ins

Dec 14, 2020
A T
8mi
Dec 5, 2020
Ram Ramgiri
Nov 15, 2020
James Bishop
Pretty mellow climb and super fun on the way down! Little extra out to Bald Mountain lookout! 9.5mi
Nov 14, 2019
J Przy
Lots of fun with great views.