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Fifield-Cahill Ridge Trail Exploration

Although this trail is not open for walk-in use by the general public, volunteer trail leaders head trips 3x a week.
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Rating: 5 out of 5 by EveryTrail members
Difficulty: Moderate
Length: 10 miles
Duration: Half day

Overview:  Local nature lovers can enjoy the rare opportunity to hike, bike, or ride their horses through pristine stands of old growth Douglas... more »

Tips:  Reservations: Online Request Form Call for more info: (650) 652-3203

*Trailhead Locations*

1. Skyline Quarry – access to this... more »

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Points of Interest

1. Fifield-Cahill Ridge Trailhead

The opening of the Fifield-Cahill Ridge trail on Aug. 21, 2003 was notable enough to garner a commemorative plaque and a press conference with then-mayor Willie Brown. The 10-mile trail runs through the watershed that provides and stores drinking water for the San Francisco Bay area. It's a property full of history, reservoirs, and rare and... More

2. Monterey Cypress Grove

A mile into the trail is a densely packed stand of Monterey Cypress. You might think cypress from nearby Monterey would be native, but in fact, these trees don't naturally grow this far north. They were planted here in the mid-30s, but why and by whom remains a bit of a mystery. The water agency may have believed the trees would gather fog drip,... More

3. Douglas Iris

Having been protected for over 100 years, the area along the Fifield-Cahill trail hosts an abundance of plant varieties, and quite a palette of wildflowers in the spring. Here, a Douglas iris.

White, perfumey blooms fill the branches of this Ceanothus tree. Ceanothus is a member of the lilac family that does well in our Bay Area climate. These... More

4. Lower Crystal Springs Reservoir

A lookout point affords a view of Lower Crystal Springs reservoir. The dam that created the reservoir was built in 1888 of interlocking concrete blocks. It survived the 1906 earthquake relatively unscathed, even though the San Andreas fault lies only a quarter mile to the west.

Panning the view from the overlook, you can see most of the Bay Area on... More

5. Cemetery Gate, Accessible Trailhead

At Cemetery Gate, a trailhead marks the start of a one-and-a-quarter mile stretch of trail that's accessible for wheelchairs. You can reach the trailhead via Skylawn Cemetery (hence the name), just north of where Skyline Blvd. meets Highway 92. Like other sections of this trail, the accessible portion is available through advance reservation only.

... More

6. Planted Douglas Fir Grove

The accessible trail passes through two very different groves of Douglas fir. This first grove is a group of trees that was planted in the 1960s. At the time, foresters believed that planting trees was the best approach to conservation. Some forest managers have changed their views, however. This forest, for example, now needs to be actively... More

7. Fungus Rot

Along any forest trail, you're likely to see fungus on a few tree trunks. Some fungi help trees, others can take a toll. This little brown shelf is evidence of heart rot, a disease that affects hardwood trees all over the world. It begins when broken tree bark exposes the wood of a tree to the fungus. This particular fungus is Polyporus... More

8. Skyline Ridge

A rest stop along the way presents us with a vista of the watershed...

...and a few logs to serve as picnic benches. Lunch with a view. And just when you need it, there's a bathroom off to the left.

9. Pilarcitos Resevoir

The area around Pilarcitos reservoir produces an enormous amount of water, held in by exquisitely engineered dams built during the Civil War era. Here, air masses come off the ocean and over the hills, cool, and dump rain. And more rain. It can rain two or three times more in this little valley than in some of the surrounding areas.

Pilarcitos... More

10. Serpentine Grasslands

This grassland area has soils that are rich in serpentinite (the state rock that you may remember from Waypoint #1). Our state rock lends heavy metals like chromium and nickel to the soil, while offering smaller-than-usual amounts of nutrients like nitrogen and phosphorus. Not the friendliest chemistry for many plants, but the flora in this region... More

11. Pacific Stonecrop

The Pacific stonecrop (Sedum divergens) is a pretty little succulent that's native to northern California, as well as the Pacific Northwest. In summer it blooms with bright yellow flowers.

The stonecrop leaves start out green, and those that get more sunlight turn pinkish-red. In this image you can see the creeping rhizomes or stolons (above-ground... More

12. Lupine Habitat

Near the end of the trail are rocky hillsides covered with a variety of lupines. Lupines have a distinctive star-shaped pattern to their leaves and upright flower stalks that bloom in the spring.


There are over 80 species of lupine in California, and they live in a variety of habitats. This species, a silver bush lupine (Lupinus albifrons), is... More

13. San Andreas Lake

From the top of the trail's last hill, you can see San Andreas Lake, so named because it sits right on the San Andreas fault. This view rounds out the tour of San Francisco's water supply, being the fourth reservoir you see from the trail. The earlier reservoirs were (in order): Lower Crystal Springs, Upper Crystal Springs, and Pilarcitos.

This... More