Devil’s Slide is a name given to a steep rocky coastal promontory located 4 miles (6.5 km) south of the Linda Mar District of Pacifica and 2.5 miles (4 km) north of Montara, California. The terrain is characterized by impressively steep eroding slopes with natural gradients ranging between 30% and 50%.
Immediately east of Devil’s Slide is a section of old California State Route 1, built between 1935 and 1936, well known for landslides and erosion that often occur during winter storms that sometimes make the road impassable. The first major landslide destroyed much of the road in 1940. Another large slide in 1995 forced the road’s closure for almost two years. In 2013, the old road was closed and replaced with the Tom Lantos Tunnels that routes the highway through the promontory behind the precarious cliffs. On March 27, 2014, the 1.3-mile (2.1 km) Devil’s Slide Trail was opened to the public. This project converted the old section of the roadway to a pedestrian and bicycle route.
Devil’s Slide was the location of a military triangulation station and observation site used during World War II as part of the harbor defense of San Francisco. In the days before radar, a ship’s precise location could be determined by triangulation. Military personnel used binoculars and compasses to search for ships at sea and relay their coordinates to a command post. There were six military structures at the Devil’s Slide including three steel-reinforced concrete observation posts, two concrete and earth bunkers, and a reinforced steel observation tower. The site was sold to a private owner after the war, but some of the structures remain. Read more here and here. Explore more of Devil’s Slide here: