MTB Project Logo

"Mount Tam", the heart of Marin County, is considered the birthplace of modern mountain biking.

Your Rating: Rating Rating Rating Rating Rating      Clear Rating
Your Difficulty:
Your Favorites: Add To-Do · Your List
Zoom in to see details
Map Key







2,326' 709 m


185' 56 m


2,450' 747 m


2,448' 746 m



Avg Grade (3°)


Max Grade (9°)

Dogs Leashed

E-Bikes Not Allowed


From shady redwoods to expansive views of San Francisco Bay to the Pacific Ocean, the ride climbs the Old Railroad Grade Trail to the summit then descends on the Eldridge Grade Trail to the north, connecting with the Indian Fire Road and Hoo-Koo-E-Koo Fire Road to loop back to the start.

Need to Know

Limited pull-out parking near Blithedale Park, though street parking is available on Blithedale Ave. all the way back to town.


Starting near the end of W. Blithedale Ave. at Blithedale Park, the Old Railroad Grade Trail is a gradual but steady climb all the way to the summit of Mt. Tam. Following a redwood-shaded creek, keep left as a couple fire roads branch to the right. Riders will find themselves eventually crossing the creek and climbing to an obvious viewpoint overlooking San Francisco Bay. The beginning of a paved section starts just past the overlook. Keep right on paved Fern Canyon Road for a little over a half-mile to the gate and continuation of the dirt trail.

Keep right at the junction with the Gravity Car Fire Road (log barriers next to trail) and climb several switchbacks called "The Double Bow Knot" which gave the old railroad its moniker: "Crookedest Railroad in the World." Note the junction with the Hoo-Koo-E-Koo Fire Road which will be used on the return loop.

Historic West Point Inn is the natural rest stop with views of the Bay and picnic tables. Lemonade, coffee and other refreshments are for sale in the summer.

From the Inn, it's a short albeit rockier climb to the summit. At the junction with the paved East Ridgecrest Blvd., note the gate directly across which is the start of the Eldridge Grade. Continue on the paved trail that parallels the road to reach the summit parking area. Bring a lock and walking shoes for the short hike to the summit fire lookout.

Heading down Eldridge Grade is steep, loose, and rocky just past the gate, but becomes less steep and alternates between rocky, pinball sections, to smooth and fast as it progresses. Take in some nice views from Inspiration Point and the next switchback at the Wheeler Hiking Trail. The road is smooth and fast at this point so keep an eye open for the Indian Fire Road junction a short distance on the right.

The Indian Fire Road winds through some trees then drops fairly steeply down a sandstone section, that can be slick, just before the junction with the Hoo-Koo-E-Koo Fire Road which loops around the mountain with a few minor climbs to the junction with the Old Railroad Grade.

History & Background

When private land donations created the Muir Woods National Monument and Mount Tamalpais State Park in the early 1900's, Mount Tam became a popular summer and weekend destination serviced by railways connecting the ferry ports on the bay all the way to the summit. Gravity rail cars would bring vacationers from the Summit Tavern down to Muir Woods and stage coaches would travel to Stinson Beach. Today, mountain bikers and hikers use these rail and stage routes to climb and traverse Mount Tam.

In the late 1970's, a group of local bikers started venturing off-road on local trails and fire roads experimenting with customized cruisers and clunkers to help spark what would become the sport of mountain biking. Names like Gary Fisher, Charlie Kelly, Tom Ritchey and Joe Breeze started out as the Marin Repack Road Clunker Clan.


Shared By:

Bob Gardner with improvements by Ryan Pechulis

Trail Ratings

  4.1 from 60 votes


in Marin County


  4.1 from 60 votes
5 Star
4 Star
3 Star
2 Star
1 Star
Recommended Route Rankings


in Marin County


in California


203 Views Last Month
43,588 Since Dec 30, 2015



Sunrise on MT Tam, April 2013. Mill Valley, CA
May 17, 2013 near Mill Va…, CA
Approaching Mount Tam summit on Old Railroad Grade.
Jan 7, 2016 near Larkspur, CA
Not a bad view eh?
Nov 22, 2015 near Larkspur, CA
The view of San Francisco on the climb up Mt Tam.
Jul 16, 2019 near Larkspur, CA
Gorgeous Bay Vista - broke my stride!
Nov 11, 2021 near Corte M…, CA
West Point Inn rest stop.
Jan 7, 2016 near Mill Va…, CA


Current Trail Conditions

All Clear 9 days ago
Add Your Check-In


Nov 16, 2023
Ron Wright
Nov 11, 2023
Connor Yap
Apr 23, 2023
V Man
Trail in decent shape - started out before 8 am to avoid traffic - trail had much more traffic after 9 am on the way down the mountain. 14mi — 1h 30m
Dec 18, 2022
Alika Gesuale
3h 30m
Nov 18, 2022
Philipp Roessler
Nov 12, 2022
Baldo Faieta
Oct 2, 2022
Amy Nye
Oct 9, 2021
josh S
a good fitness ride. all fire roads, great views though 16mi — 2h 20m