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Mount Tamalpais Summit Loop


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

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2,326' 709 m


185' 56 m


2,450' 747 m


2,448' 746 m



Avg Grade (3°)


Max Grade (9°)

Dogs Leashed

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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

Trail Ratings

  4.0 from 45 votes


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  4.0 from 45 votes
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653 Views Last Month
36,917 Since Dec 30, 2015



Sunrise on MT Tam, April 2013. Mill Valley, CA
May 17, 2013 near Mill Va…, CA
Not a bad view eh?
Nov 22, 2015 near Larkspur, CA
Approaching Mount Tam summit on Old Railroad Grade.
Jan 7, 2016 near Larkspur, CA
The view of San Francisco on the climb up Mt Tam.
Jul 16, 2019 near Larkspur, CA
Mount Tam's endless views.
Jan 7, 2016 near Larkspur, CA
Mount Tam summit bike repair station
Jan 7, 2016 near Larkspur, CA


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Jun 5, 2021
James Bishop
May 8, 2021
Rob Metzgar
Apr 5, 2021
Kathryn Koehler
Owen and Mike on his fancy demo bike. Super rocky, beautiful but boring. 19.7mi — 2h 57m
Jan 3, 2021
Nathan Leavitt
3h 12m
Dec 7, 2020
Gary Michelsen
16.1mi — 2h 17m
Nov 21, 2020
Adam Brill
Amazing ride. 15.5mi
Nov 16, 2020
Kevin Hu
Nov 14, 2020
Steve McEfee