The best gravel rides in Marin County

The Phoenix Lake – Fish Gulch trail junction loop from Mill Valley offers a demanding yet incredibly scenic gravel biking adventure. You'll wind through diverse landscapes, from the cool shade of redwood forests to sun-drenched oak woodlands and open grasslands, with the promise of sweeping views of the Pacific Ocean and Golden Gate Bridge from higher points near Mount Tamalpais. This route is a true test of endurance, featuring steep and loose sections that demand very good fitness and bike handling skills.

Planning your ride requires a bit of foresight; while much of the loop is prime for gravel biking, be aware that the immediate trails around Phoenix Lake itself may not allow bikes. Parking is generally available in Mill Valley, but it's always wise to arrive early, especially on weekends, to secure a spot. Given the route's length and elevation, pack ample water and snacks, and consider starting early to make the most of the daylight.

This loop is a standout in the Mill Valley area, celebrated by local gravel bikers for its challenging terrain and the opportunity to combine dirt climbs with rewarding road descents. It showcases the region's extensive trail network and significant elevation gains, making it a prime destination for those looking to push their limits and experience the natural beauty of Marin County.

This Sausalito — Mill Valley Path – Alpine Dam loop from Marin City offers a varied cycling experience, blending flat paved multi-use paths with challenging road climbs and opportunities for gravel sections. You'll start with picturesque views of Richardson Bay and Mount Tamalpais from the Mill Valley-Sausalito Multiuse Pathway before ascending into the Mount Tam Watershed, where redwood forests and lakes provide a dramatic backdrop. The route culminates with panoramic vistas of the Pacific Ocean and San Francisco Bay from Ridgecrest, making it a truly iconic Marin County ride.

Rated as "difficult," this 39.5-mile (63.5 km) route involves a substantial 3794 feet (1156 metres) of elevation gain, typically taking around 4 hours and 24 minutes to complete. While the initial pathway is easy, the Alpine Dam loop introduces significant climbing, with steep and twisty sections that demand good fitness. Consider an early start to enjoy quieter roads, especially around Alpine Lake, and ensure you're prepared for a sustained effort.

Known as a "crown jewel" of Marin County cycling, this loop is celebrated for its diverse landscapes and stunning viewpoints. It offers excellent potential for gravel biking enthusiasts to integrate nearby fire roads and trails around Mount Tamalpais for an even greater mixed-surface challenge. The route also traces a former railroad corridor, connecting you to the rich history and natural beauty of the region.

This Novato San Marin gravel biking route offers a delightful blend of smooth, paved multi-use paths and natural fire roads, making it an excellent choice for a varied ride. You'll start on the tree-lined SMART Multiuse Pathway, enjoying a comfortable surface before transitioning to the Pinheiro Fire Road. Here, the landscape opens up to scenic marsh and oak views within the Rush Creek Open Space, providing a more natural, open-space feel.

This easy 11.6-mile (18.7 km) loop, with a gentle 302 feet (92 metres) of elevation gain, is suitable for all skill levels and can typically be completed in about 1 hour and 22 minutes. It's a family-friendly option, and dogs are permitted on the Pinheiro Fire Road section. While generally accessible year-round, be aware that the unpaved sections of Pinheiro Fire Road can be bumpy or wet after rain.

The SMART Multiuse Pathway is part of a larger planned 70-mile trail system, connecting communities and offering both recreational and commuting options. The Pinheiro Fire Road, a popular multi-use trail, attracts not only gravel bikers but also horseback riders and hikers, highlighting its appeal as a diverse outdoor space in Marin County.