Get Involved in Re-Opening Alto Tunnel
The single most transformative project in Marin County would be the re-opening of the Alto Tunnel to bicycle and pedestrian travel. The tunnel, dug through the ridge between Mill Valley and Corte Madera by the Northwestern Pacific Railroad in 1884, was boarded up in 1975. But since the 90s, advocates have pushed to repurpose the Alto Tunnel, and other tunnels like it, for active transportation use, allowing people to bypass hills and avoid busy roads.