Don't Ride them yet! New trails Under Construction in Mill Valley and West Marin

The Marin County Open Space trail crew is hard at work on a number of bike related trail projects across the County. They are wrapping up the reroute of “the Plunge” on Old Railroad Grade Trail near White Hill in Fairfax, which includes a gentler grade and a bridge to replace the steep and erosive “Plunge.” Further west, crews are working on the 2-mile Contour Trail Complex, which includes three trails that will make a nice loop option in the Giacomini Open Space Preserve. Lastly, they are working on a multi-use connector near the summit of Camino Alto Road and a hiker/biker trail from Escalon Fire Road down to Del Casa Road in Mill Valley. MCBC plans to celebrate the completion of all these projects with an event at the Plunge in late October or early November – we’ll confirm that date soon.


Additionally, MCBC proposals for upgrading the Bob Middagh Trail and adding protective bridges over San Anselmo Creek in Cascade Canyon have been publicly vetted and are in comment period.

We propose upgrading the .4 mile Bob Middagh Trail from dual use (pedestrian/equestrian) to full multi-use to accommodate safe connectivity between the Alto Bowl and Camino Alto Open Space Preserves for pedestrians, cyclists, and equestrians. The trail already maintains a 5 foot bench, wider than the typical 48″ standard for multiuse trails. 90% of the existing alignment has superb sight lines and a grade below 5%. There are only four short sections with below-average visibility. “Slow & Say Hello” signs coupled with pinch points will moderate speed at these sections. This proposal would improve connectivity to Region 1 Open Space preserves for bicyclists living in the Alto Bowl neighborhoods of Mill Valley and Corte Madera and would improve safety for bicyclists by providing a new route with less vehicular traffic.

Open Space proposes a few reroutes and switchbacks to reduce the grade (see photo below). If you haven’t voiced your support for the Bob Middagh Trail proposal and would like to, please contact Tom Boss.


The Region 3 trail designation is also in comment period following an initial designation workshop in August. MCBC is excited about the prospect of a new 5+ mile XC trail loop at the Eastern end of Big Rock connecting notoriously steep Chicken Shack Fire Road with Marinwood and Ignacio. There is also an opportunity for better connectivity in the Indian Valley Open Space Preserve, which avoids trails popular with equestrians.


At the time of this posting, we received word that some bicyclists are riding on the trail under construction in the Camino Alto Open Space Preserve and that it’s impacting progress. The trail is getting a REAL good soaking each day and afternoon so the tread settles in. It will make it more stable this winter. Unfortunately the crew is finding bike tracks down the middle of the wet/muddy trail every morning. which forces them to go back and fix the ruts. Someone is also tearing down multiple layers of yellow closure tape to get on the trail. Please help us get these trails officially open as soon as possible by staying off trails under construction and telling your friends to do the same!

Thank you!

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