Alto Tunnel
Top Categories
Call to Action: Support Opening the Alto Rail Tunnel for Cyclists and Pedestrians
It would provide a safe, fast, and level route between Mill Valley and Corte Madera/Larkspur
Marin County Bicycle Coalition
February 10, 2026
Engineers Lay Out Costs of Reopening Alto Tunnel to Bicyclists
Addressing a crowd of more than 100 people Wednesday, engineers said it could cost $40 million to $52 million to reopen the crumbling 125-year-old railroad tunnel between Mill Valley and Corte Madera for cyclists.
December 10, 2009
Alto Tunnel Workshop Draws Standing-Room-Only Crowd
A large and divided crowd turned out last night in Marin County to help decide whether the long-neglected Alto Tunnel between Mill Valley and Corte Madera should be reopened to cyclists.
March 5, 2009
Workshop Tomorrow on Marin’s Alto Tunnel
Cycling enthusiasts have long dreamed of reopening the rotting, 125-year-old Alto
Tunnel as a key link in a greenway stretching from the Golden Gate Bridge to
Cloverdale. Now they may get their chance, as the county's Non-motorized
Transportation Pilot Program begins a $225,000 study of three routes between the two southern Marin towns.
March 3, 2009