NileGuide Expert Says:
You have to pay to access this mountain biking area, but it's well worth it, as the trail was built and is maintained with mountain bikers in mind!
1000 Iron Springs Rd
San Rafael, CA 94930
NileGuide Expert tip:
Buy the pass for just $5 at any bike shop in the nearby town of Fairfax
Built specifically for mountain bikers, this rugged loop approximates the perfect ride. Nine miles of continuous singletrack passing through all variety of vegetation - chaparral fields, towering redwood groves, "one match" meadows, rock gardens, and creek crossings - connected with long switch-backing ascents and descents. Counter-clockwise may be the better route (debatable) as this sends you down the Serpentine Trail - a long, steep series of tight switchbacks.
It's also a great place to go hiking, as long as you don't mind the the mountain bikers.