Waldo Grade

Waldo Grade is a mountain road in Marin County that connects San Francisco with northern communities, extending roughly 4 kilometers through hilly terrain. The route passes through two tunnels and provides multiple traffic lanes in each direction.

The road opened in 1937 and required extensive blasting plus construction of two tunnels through Marin County's hills. The project was a major infrastructure undertaking that connected San Francisco with the north.

The name comes from William Waldo, a California politician from the 1850s whose influence shaped this route's identity. The area reflects its role today as a vital link where commuters experience daily traffic patterns that connect two distinct regions.

Drive with care through the two tunnels, particularly on rainy days when conditions become challenging. Keep in mind this is the main route between two regions and can be very crowded during rush hours.

Heavy storms in January 1982 caused major landslides that forced a complete closure and evacuation of residents. This event revealed the vulnerability of this mountain route to extreme weather conditions.

Location: California

Official opening: 1937

GPS coordinates: 37.84300,-122.48600

Latest update: December 10, 2025 15:56