Some of the area’s open space preserves are only accessible as guided hikes. The Fifield-Cahill Ridge Trail is one such trail that provides supervised access to the protected lands of the San Francisco Peninsula Watershed. Managed by the San Francisco Public Utilities Commission (SFPUC) , the Crystal Springs, Pilarcitos, and San Andreas Reservoirs are located within this watershed. Hikes are allowed three times a week on Wednesdays, Saturdays, and Sundays.
In order to hike the Fifield-Cahill Ridge Trail, participants will need to reserve a spot on one of the listed docent-led hikes along this 10-mile long trail. This route features some pretty rigorous elevation gains and is considered to be a challenging hike.
11-mile hike
The trail length and starting point varies, with hiking and biking outings. The Fifield-Cahill Ridge Hike is popular with people completing the Bay Area Ridge Trail Circumnavigation challenge. I signed up for the 11-mile through-hike version, which is one of the more popular hikes to take. This hike is the longest offered although for bikers there are much longer events you can sign up for.
The 11-mile hike-through started with meeting outside the Skylawn Cemetery along Route 82 in Half Moon Bay and then caravanning to the Cemetery Gate Trailhead located behind locked gates. We then piled ourselves into two cars to drive over to the trailhead located behind Skyline College. There is a small parking lot (Lot C) with four spaces reserved for accessing the Notch Trail.
Notch Trail
Notch Trail starts the hike in the Golden Gate National Recreation Area which is open to the public. The first 1.6 miles of this hike features some fairly steep elevational climbs with gradients ranging from 10% to 17%. There are several sections with steep stairs as you pass through coast sage scrubs and chaparral plant communities. Spotted towhees are busy calling from the shrubs this time of year.
If you hike this trail during the late summer months, the “May gray” and “June gloom” is pretty dominate. The marine layer brought a thick blanket of fog during our late May hike. We quickly ascended into the fog, which blocked the normally expansive views along the entire length of the trail.
As we got to the top of the ridge, strong winds and mist also greeted us. Dressing in layers and making sure your hat is secure are a must for hiking this trail during this time of the year. If you prefer a sunnier weather, make sure to book your docent hike later in the summer or early fall.
Sweeney Ridge Trails
Notch Trail junctions at Mori Ridge Trail (which heads west towards the Pacific Ocean to Mori Point) and Sweeney Ridge Trail. We continued our hike south along Sweeney Ridge Trail before stopping at the former Radar Control Site for Nike Site SF-51.
Continuing south along Sweeney Ridge Trail, we stopped at the Discovery Site which features two serpentine rock monuments one of which commemorates Juan Gaspar de Portolá first sighting of the San Francisco Bay.
Portola Gate – Entry point for the Fifield-Cahill Ridge Trail
Sweeney Ridge Trail terminates at the Portola Gate. Access beyond and onto the Fifield-Cahill Ridge Trail requires a docent who has access to unlock the chain linked fence.
Once past the locked gate, we were greeted by a GGNRA ranger who explained the rules and safety guidelines for the rest of our hike. While some docent-led hikes are more interpretive in nature, most of this hike was done at a fairly decent clip. The hikers on this 11-mile hike seemed to mostly be interested in hiking so our pace averaged about 3 miles-per-hour. We were allowed to hike ahead of our docent as long as we didn’t get too far ahead and stayed on the route.
The Fifield-Cahill Ridge Trail is mostly a gravel service road that winds its way through grasslands, Douglas-fir woodlands, and coastal scrub plant communities.
Up along the ridge, most of the hillside is covered with grasslands and chaparral plant communities. There are pockets of the trail that pass through small groves of mature Douglas-fir woodlands. The heavy fog lent a mystical atmosphere as we passed through these old trees.
The strong winds and extreme temperature swings have shaped the growth of these Douglas-fir trees. Unlike the tall and single stem growth pattern common in mixed coastal redwood and Douglas-fir forests found in many areas of the Santa Cruz Moutains, the conifers along the Fifield-Cahill Ridge Trail are windswept. The persistent coastal wind has shaped the Douglas-fir trees into twisted, gnarled forms with uneven, lopsided trunks.
A short little offshoot from the Fifield-Cahill Ridge Trail provides access to a picnic area with views of the Pilarcitos Reservoir through the trees. Pilarcitos Reservoir was built in 1866 and was the first major reservoir built for San Francisco.
Our hike continued to descend towards the end point of our hike at the Cemetery trailhead. Here, the trail passes through denser second-growth Douglas-fir trees. The effects of the wind are diminished and more birds can be seen and heard calling through the trees.
We make it back to the end point at the Cemetery trailhead in just until 4 hours of total moving time. Our docent, Thomas, remarks about the quick pace of our group, noting it was “one for the record books.” A typical 11-mile Fifield-Cahill hike takes between 5-7 hours which includes two rest stops along the way (one longer one for lunch).
