4.8
(14)
178
riders
23
rides
Gravel biking in Sierra Azul Open Space Preserve offers an extensive trail system within the rugged Santa Cruz Mountains. The preserve features significant elevation changes, with trails ranging from challenging climbs on old fire roads to varied terrain including serpentine grasslands, dense oak woodlands, and deep ravines. Prominent peaks like Mount Umunhum and Mount El Sombroso contribute to the landscape, providing panoramic views.
Last updated: July 11, 2026
5.0
(2)
8
riders
Hard gravel ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.
10
riders
Hard gravel ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.

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12
riders
51.5km
03:41
900m
900m
Hard gravel ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.
10
riders
38.0km
03:15
1,080m
1,080m
Hard gravel ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.
6
riders
25.9km
02:01
740m
740m
Hard gravel ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.
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This is not a very exciting trail to hike. It’s pretty much a trail surrounded by thick walls of vegetation, with almost no opportunity to view your surroundings. The trail is 70% rocks/gravel, and 30% hard packed clay, so avoid wearing snickers
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If you make the summit a fantastic view awaits. Be aware the road goes down then up to the road about then up again to the summit!…
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Great bar. Friendly helpful staff/owner simple ordering system. Great place to watch the world go by with a beer 🍻
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Still one of the highest points in the Santa Cruz Mountains, even though the military graded and flattened the actual summit to create an Air Force base. The summit was cleaned of hazardous material in 2009, then carefully restored after a lot of community input. It's a lovely place to visit now!
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Climbing Mount Umunhum is a tough but rewarding challenge. The road is steep, with sections reaching up to 18% grades, so pace yourself. The views from the top are spectacular, making the hard work worth it. Start early to avoid traffic and the heat, and be prepared for a long, demanding ascent.
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Shannon Road starts with a gentle climb from Los Gatos Creek to Blossom Hill Park, then transitions into a steeper ascent as it leads into a rural area. The summit below Blossom Hill offers a rewarding challenge and connects to other routes in the area.
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Nice gravel trail that winds its way through the park. Some sections follow long the water giving you some great views.
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There are over 29 gravel bike routes in Sierra Azul Open Space Preserve, offering a wide range of experiences for riders looking to explore the rugged Santa Cruz Mountains.
The preserve is known for its rugged and steep landscape, with significant elevation changes. Most routes are rated as difficult, providing a good workout. Trails often consist of old fire roads, which can be persistently steep in some areas, requiring advanced riding skills or even pushing your bike on certain sections.
While many trails are challenging, some sections offer more moderate terrain. For instance, parts of the Lexington Reservoir – Los Gatos Creek Trail loop from Oak Meadow provide varied terrain that can be enjoyed by those with some gravel biking experience, though it is still rated as difficult overall due to elevation changes.
You'll encounter a diverse environment, including serpentine grasslands, rocky chaparral, dense bay tree stands, shaded oak woodland forests, and deep ravines. The trails often follow old fire roads, which contribute to the significant elevation changes and varied surfaces.
The preserve offers expansive views from various points, including the summits of Mount Umunhum and Mount El Sombroso. You can see the Santa Clara Valley, ridgelines, and other Bay Area peaks. The Mount Umunhum Road (climb) leads to the summit of Mount Umunhum, offering incredible panoramic views and the distinctive Cold War-era radar tower.
Yes, several popular routes are circular. For example, the Mine Hill Trailhead – Mine Hill Trail loop from Almaden Quicksilver County Park and the Mine Hill Trailhead – Lisa Killough Trail loop from Almaden Quicksilver County Park are both excellent circular options that navigate diverse landscapes.
The preserve can be enjoyed year-round, but spring and fall generally offer the most pleasant conditions with milder temperatures. Summers can be hot, and some trails may be dusty. Winters bring cooler weather and potential for rain, which can make some trails muddy and challenging.
Public transport options directly to the trailheads are limited. Most visitors access the preserve by car, with parking available at various trailheads. It's advisable to check local transit authority websites for the most current information on routes that might get you close to the preserve's edges.
Generally, permits are not required for individual gravel biking in Sierra Azul Open Space Preserve. However, it's always a good idea to check the official Midpeninsula Regional Open Space District website for any updated regulations or specific trail closures before your visit.
The area is highly rated by the komoot community, with an average score of 4.7 stars. Reviewers often praise the challenging climbs, the diverse and rugged landscapes, and the rewarding panoramic views from the peaks. The extensive multi-use trail system is also a significant draw.
The varied habitats of Sierra Azul are home to abundant wildlife. You might spot deer, bobcats, and coyotes. Mountain lions are also present, so it's important to be aware of your surroundings and follow safety guidelines for wildlife encounters.
While there are no facilities directly within the preserve, the nearby towns of Los Gatos and San Jose offer a variety of cafes, restaurants, and accommodation options where you can refuel and relax after your gravel biking adventure.


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