Marin’s iconic ridge, Mount Tamalpais, is a magnet for serious mountain bikers, many of whom come to ride one of the classic routes to the top: Eldridge Grade. The route, located on the mountain’s northern watershed slopes, doesn’t offer any single track but is a fire road with attitude. 

The best starting point for this half-day ride is street parking in or around Ross Common in the charming town of Ross. From Ross, you ride down mansion-lined Lagunitas Road to tiny Natalie Coffin Green Park, where a fire road heads up a short distance to Phoenix Lake, one of the county’s water district reservoirs.

Eldridge Grade starts at the far western edge of Phoenix Lake and ascends all the way to the parking lot at East Peak, first rising gradually (about 7% on average) through a shady forest of redwood and bay trees into open slopes of brushy chaparral. As you get higher, the trail gets rockier and rockier, and changes from a steady cruise to technically challenging.

The workout is worth it though, as you eventually reach Tam’s East Peak, where you can refill water bottles and enjoy wide views of the bay and city. If you bring a bike lock, you can take a quick stroll on Verna Dunshee Trail, a hiking-only trail that circumnavigates the peak and offers outstanding views of San Francisco Bay, Pacific Ocean and southern Marin. You can return to Phoenix Lake on Eldridge or continue up the paved road to access the Rock Spring fire road, which offers a thrilling descent to Lake Lagunitas and options for returning to Phoenix Lake and Ross via the Lakeview Fire Road, Filter Plant Road, Shaver Grade or Fish Grade trails.

For a complete map of the route and other road and mountain bike route in Marin, visit the website of the Marin County Bicycle Coalition. A map is included with membership or can be purchased at local bike shops.