A hiker reported that a four-door sedan had driven off the side of the road and crashed about 500 feet below.
Emergency crews responded to the area and had to establish a long-line rescue system due to the difficult terrain.
Marin County fire battalion chief Bret McTigue told KTVU the heavily-damaged sedan overturned and the engine was thrown from the vehicle. Authorities found the driver, the sole occupant, dead inside.
"The area where the collision occurred is a busy hiking area, as well as a very popular route for cyclists to ride, especially on nice weekends," CHP Marin said. "Out of an abundance of caution a CHP helicopter responded to the scene and assisted with a search to ensure there were no other individuals that were struck by the errant vehicle."
Another helicopter from the Sonoma County Sheriff's Office was used to bring the body of the driver back to the roadway.
Officials said the driver's name is not being released as the Marin County Coroner still needs to identify and make notifications to next of kin. The cause of the crash remains under investigation, and any toxicology will not be known for some time, according to CHP.