The Dias Ridge Trail, in the Marin Headlands in southwestern Marin County, was realigned/rebuilt and then added to the Bay Area Ridge Trail system in 2010. About half of the trail is within the Golden Gate National Recreation Area and the other half is within Mt. Tamalpais State Park. The trail provides a beautiful and popular trail connection between CA-1 and the main route of the Bay Area Ridge Trail.
Dias Ridge is named after Silvio Dias, one of the Portuguese dairy ranchers with landholdings in the West Marin hills. One of the dairy ranches was called the Golden Gate Dairy, and today the Golden Gate Dairy Stables are located at the lower elevation trail head on CA-1.
My out-and-back hike started and ended at the parking area at Muir Beach. The day of the hike, which happened to be Fathers Day, was one of the somewhat rare clear days along the Pacific coast. Though there was a sign posted at the CA-1 end of the access road indicating that the parking lot was full, I decided to try my luck anyway, since the day was so perfect for this hike. After about a half-hour wait, I was able to grab a parking spot when someone else departed. It was well worth the wait!
After walking back up the access road (about 0.3 mile) and crossing CA-1, the trail head is well-marked and easy to find. The trail immediately starts to climb, with several switchbacks easing the grade.
Looking down toward the beach, I was rewarded with wonderful views from several locations.
Even though the day was relatively clear, wisps of fog drifted over the hills.
The path of the trail goes roughly parallel to CA-1, which goes down Green Gulch to Muir Beach. Several trails were visible across the gulch, criss-crossing the side of Coyote Ridge.
From the trail head the trail gains about 750 feet in 1.5 miles, for an average grade of slightly under 10%.
About 1.8 miles from the start (1.5 miles from the trail head) there is a sign indicating the boundary of the Golden Gate National Recreation Area (GGNRA). Beyond the sign is Mt. Tamalpais State Park. For some reason I find it curiously interesting that Mt. Tam is almost completely surrounded by lands of the Marin Municipal Water District Watershed, with a narrow corridor of the State Park surrounding the road to the Visitor Center at the main (East) Peak.
The GGNRA – State Park boundary is nearly at the highest point of the Dias Ridge Trail. Within the State Park, the trail undulates less than 200 feet. This indicates an impressive feat of trail design, given the terrain. At the location where the trail makes a sharp turn to the right, near the word State in the GPS track, there is a beautiful clear view of Mt Tamalpais across Muir Woods National Monument.
Although the trail is mostly in open grasslands, it passes through a lovely grove of trees.
About 3.0 miles from the start (2.7 miles from the trail head) the Miwok Trail (the main Bay Area Ridge Trail route in this area) crosses the Dias Ridge Trail; there is a jog of perhaps 100 yards where the trails coincide. The Dias Ridge Trail continues another 0.3 miles to a trail head on Panoramic Hwy, the route from CA-1 to Mt. Tamalpais. The full length of the trail, from trail head to trail head, is 3.0 miles, noted as 3.1 miles in other descriptions of the trail.
By the time I had returned to the Miwok Trail junction, I could see ahead of me that more and more fog was starting to appear over the hills.
This is a typical pattern for the afternoon, and I was grateful for what had been several hours of relatively clear weather between the morning burn-off and the afternoon return of the fog. Some days the clear gap is very short, or even nonexistent, near the coast.
I was very curious to see how Muir Beach would look returning back down the hill. Not surprisingly, the famous fog bank had moved much closer to shore.
On some hikes I tend to save picture-taking for the return trip. How fortunate that I appreciated the clear weather at the start of this hike and took pictures to remember the sights! It is noteworthy that the time difference between these two pictures of Muir Beach was only an hour and a half.