4.0
(6)
106
riders
14
rides
Gravel biking in French Ranch Open Space Preserve offers diverse landscapes across 403 acres in Marin County, featuring multiuse fire roads suitable for cycling. The preserve is characterized by deep, forested canyons with redwood and oak groves, ascending to ridges that provide expansive valley overlooks. Riders will encounter varied terrain, including areas with unique serpentine soil and sections of the Lagunitas Creek watershed.
Last updated: July 10, 2026
3
riders
15.9km
01:33
490m
500m
Hard gravel ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.
4.0
(2)
36
riders
65.9km
04:42
1,010m
1,010m
The Alpine Dam – Alpine Lake loop from Sleepy Hollow is a crown jewel among Marin County gravel biking routes, offering an incredible journey through varied landscapes. You'll wind through dense redwood forests, past the tranquil Alpine Lake, and experience the challenging yet rewarding terrain of the Mt. Tam Watershed. Keep an eye out for stunning viewpoints of Mount Tamalpais and even the Pacific Ocean from sections like the "Seven Sisters" on this 40.9-mile (65.9 km) adventure with 3311 feet (1009 metres) of climbing.
This difficult gravel biking route typically takes around 4 hours and 41 minutes, demanding very good fitness and advanced riding skills. For the best experience, it's generally recommended to tackle the loop in a counter-clockwise direction. Be ready for a mix of paved and unpaved surfaces, including challenging climbs and technical descents, and know that some sections might require you to dismount and push your bike.
What makes this one of the most popular gravel routes in Marin County is its combination of demanding terrain and consistently lauded scenery. Beyond the lake and dam, the region boasts diverse landscapes with oak-bay woodlands, savannas, grasslands, and forested hills, all contributing to its visual appeal. You'll also pass through charming Marin County towns, adding to the local flavor of this epic ride.

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5
riders
17.7km
01:30
390m
390m
Moderate gravel ride. Good fitness required. Mostly paved surfaces. Suitable for all skill levels.
3.0
(1)
8
riders
38.6km
03:35
950m
940m
Hard gravel ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.
9
riders
52.5km
05:00
1,510m
1,500m
Hard gravel ride. Very good fitness required. Mostly paved surfaces. Suitable for all skill levels.
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Popular around French Ranch Open Space Preserve
An absolute must-see for cycling enthusiasts! This museum in Fairfax tells the story of nearly 200 years of cycling history, from 19th-century velocipedes to modern racing bikes. It's also home to the Mountain Bike Hall of Fame, featuring unique specimens and stories about the pioneers of mountain biking. The collection is impressive and authentic—no replicas, but real bicycles that showcase the evolution of technology and design. An inspiring place where you can truly feel the passion for cycling.
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Constructed in 1917 this dam forms Alpine Lake, which sites between Kent and Bon Tempe Lakes. The road across the top of the dam make it a great place to ride on a loop around the lake.
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This lake was formed by the building of Alpine Dam in 1917. It sits between Kent Lake and Bon Tempe Lake, and is popular for a variety of outdoor activities.
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At the junction of Chicken Shack Fire Road and Ponti Ridge Trail. There are benches, a great view, and trail markers.
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West of Lake Lagunitas, Bon Tempe Lake is a reservoir managed by Marin Municipal Water District. It features striking scenery, with lush trees, clear water, and a peaceful atmosphere.
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At this point on Sky Oaks Road, there is a junction with Shaver Grade Road, which connects with a dense network of trails and dirt roads near Bald Hill in the Mount Tamalpais State Park. From here, you can continue on the paved Sky Oaks Road or go arond the gate on to the gravel Shaver Grade Road.
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Steep heading West can have traffic on SFD
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French Ranch Open Space Preserve offers a good selection of traffic-free gravel bike trails, with 11 routes currently available on komoot. These trails primarily utilize the preserve's multiuse fire roads, providing ample opportunities for gravel cyclists to explore the diverse landscapes.
The preserve is enjoyable year-round, but spring and fall offer ideal conditions with mild temperatures and vibrant scenery. During the rainy season, you might encounter more active wildlife like salamanders and snails, and spring brings an array of wildflowers. The forested canyons and redwood groves, especially around Roy's Redwoods, offer refreshing cool temperatures even during summer.
While many routes are rated moderate to difficult, the preserve's multiuse fire roads generally provide a stable surface. For a family-friendly experience, consider shorter sections of these fire roads. Always check the specific route details for elevation and distance to ensure it matches your family's ability. The area around Roy's Redwoods Open Space Preserve might offer gentler terrain suitable for a more relaxed ride.
You can expect a mix of terrains, predominantly multiuse fire roads which are ideal for gravel biking. These routes often ascend to ridges offering expansive valley views and pass through deep, forested canyons with Douglas fir, redwood, oak, and tanoak trees. Some areas, particularly the western end, feature unique serpentine soil, adding an interesting ecological dimension.
The preserve is rich in natural beauty. You can ride through majestic redwood groves, particularly near Roy's Redwoods Open Space Preserve, which is famous for being a Star Wars filming location. Ascend to Moon Hill Summit for panoramic views, or explore sections of the Roy's Redwoods Loop Trail. The preserve is also part of the Lagunitas Creek watershed, home to diverse wildlife.
Yes, many of the gravel bike routes in and around French Ranch Open Space Preserve are designed as loops. For example, the challenging Loma Alta Summit – 680 Trail loop from Marin County offers a circular experience with significant elevation gain. Another option is the Fairfax – Gestalt Haus loop from Fairfax.
The gravel bike trails in French Ranch Open Space Preserve range from moderate to difficult. Out of the 11 routes, 3 are rated moderate and 8 are rated difficult. Routes like the Phoenix Lake – Fish Gulch trail junction loop from Fairfax are considered moderate, while longer rides such as the Alpine Dam – Alpine Lake loop from Sleepy Hollow present a significant challenge with over 1000 meters of elevation gain.
While specific parking areas within the preserve are not detailed, access points often exist near the eastern start of gravel trails along Sir Francis Drake Blvd. It's advisable to check local regulations and designated parking areas in nearby towns like Woodacre or Fairfax, which serve as common starting points for rides into the preserve.
The area is highly rated by the komoot community, with an average score of 4.0 stars. Reviewers often praise the preserve's quiet, traffic-free fire roads, the stunning views from ridge overlooks, and the unique experience of riding through ancient redwood groves. The diverse terrain and challenging climbs are also frequently highlighted by experienced riders.
Yes, for those seeking a longer adventure, French Ranch Open Space Preserve and its surrounding areas offer extensive routes. The Alpine Dam – Alpine Lake loop from Sleepy Hollow is a challenging 65.8 km route, while the Fairfax – Alpine Lake - Bon Tempe Dam loop from Fairfax covers 38.5 km, both providing significant distances and elevation for experienced gravel bikers.
Public transport options directly to the trailheads within French Ranch Open Space Preserve may be limited. It is generally recommended to plan your trip by car to reach the main access points or starting towns like Woodacre or Fairfax, from where you can cycle into the preserve. Always check local transit schedules for the most up-to-date information.


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