Pacheco Valle Open Space Preserve,
Marin County Open Space District,
Marin County
In brief:
2.7 mile loop on sidewalks and fire roads near Marinwood.

Distance, category, and difficulty:
This 2.7 mile loop hike is moderate, with about 550 feet in elevation change. Trailhead elevation is around 100 feet. The preserve's high point is around 1400 feet. All the fire roads climb steeply to Big Rock Ridge.

Mostly exposed.


Trail surfaces
Dirt fire roads, one paved fire road, and paved sidewalk.

Hiking time
2 hours.

Good anytime, best in late winter.

Getting there:
• From southbound US 101 in Marin County, exit Alameda del Prado. At the base of the exit ramp, turn left at the stop sign. Drive about 0.1 mile, then look for side of the road parking on or around Clay Court (across the street from the park and ride lot).
• From northbound US 101 in Marin County, exit Nave Drive. Follow the signs to Alameda del Prado, which direct you west over the highway on Nave Drive. As you reach the stop sign at Alameda del Prado, look for side of the road parking on or around Clay Court (across the street from the park and ride lot).

Get driving or public transit directions from Transit and Trails:

GPS coordinates* for trailhead:
Latitude 38 2'53.74"N
(* based on Google Earth data, shown as degrees, minutes, seconds)

Gas, food, and lodging:
There's a Burger King on the west side of the highway near the Alameda del Prado exit ramp, and a gas station on the west side of the freeway at the Marinwood exit (the next exit southbound on 101).

Trailhead details:
Very tough parking weekdays. The park and ride lot is off limits weekdays, but acceptable on weekends. You may have to drive around for awhile to find parking. No facilities (water, maps, toilets), or parking/entrance fees. No designated handicapped parking, and trails are not wheelchair-accessible. With the Alameda del Prado Golden Gate Transit Bus Pad right across the street, this is a trailhead easy to reach by bus. Local, basic, and commute service buses stop here (routes 1, 48 and 50): visit the Transit Info website for more details.

Trails are multi-use. Dogs are permitted on leash on trails; off leash under voice command on fire roads. Dog owners must have a leash for each dog.

The Official Story:
MCOSD field office 415-499-6405
MCOSD's Pacheco Valle page

Map Choices:
• Download the Big Rock Ridge pdf map from the MCOSD website.
Trails of Northeast Marin County is the best map to this area (available from Pease Press).
Open Spaces:  Lands of the Marin County Open Space District, by Barry Spitz (order this book from has a simple map and detailed descriptions of trails (and how to find them). A very valuable guide to Big Rock Ridge.
Hiking Marin by Don and Kay Martin (order this book from has useful trail descriptions and a detailed map.

View photos from this hike.

Go to Bay Area Hiker Home page

Big Rock Ridge does not dominate the landscape like Marin County's most famous and visible mountain. Chicken Shack Fire Road starts to the left; Clay Court on the right offers side of the road parkingWhile Mount Tamalpais, the county's highest peak, is conspicuous for miles around (even from surrounding counties), Big Rock Ridge blends into the neighboring rolling hills. Simply part of a gorgeous bay area tableau, if you don't know where to look for Big Rock Ridge, you won't find it. This said, it's somewhat of a surprise to learn that Big Rock Ridge is the second highest peak in Marin County (if you count three-peaked Mount Tam as one mountain). The summit, elevation 1887 feet, is on private property, but the highest public peak (1640 feet) can be reached via the steep Luiz Fire Road at Lucas Valley Open Space Preserve. The eastern part of the ridge is owned by Marinwood Community Services District, and when you connect their land with MCOSD's Lucas Valley, Loma Verde, Ignacio Valley, and Pacheco Valle Open Space Preserves, you have a publicly-accessible landmass of over 3,000 acres. Little Cat Fire Road junction with Alameda del PradoDespite the acreage, there are few official trails, and only a handful of fire roads, most of them quite steep. With residential neighborhoods squeezed around the base of the ridge, parking is often a difficult proposition, and any loop hikes require some time spent pounding the pavement of Novato and Marinwood's suburban sidewalks and/or bike paths.
     At the end of Marinwood's Queenstone Road, Big Cat Fire Road (also called Queenstone Fire Road on some maps) rises through Big Rock Ridge's southeastern section. This trailhead offers no facilities, but is easy to find and boasts some side of street parking. Other than the previously mentioned trailheads at Lucas Valley and Pacheco Valle, you can explore the ridge from the north via Loma Verde and Ignacio Valley Open Space Preserves, at tiny trailheads on Pebble Beach Drive, Posada del Sol, Via Escondido, Winged Foot Drive, and Burning Tree Drive. Climbing on Little Cat Fire RoadUse Barry Spitz's Open Spaces and a detailed road map to find these trailheads if you're not familiar with the area. Note that the preserves border private property, so this is not a good location to go off trail.
     Virtually every hike entails a stint on Chicken Shack Fire Road, the main trail along the ridge. If you'd like a grand tour of Big Rock Ridge, you can walk on a bike path, sidewalk, and then fire roads for a challenging 7 mile loop. Start at the Clay Court Trailhead and walk south on a bike path that parallels 101. After about 1.2 miles, the path ends at Miller Creek Road near Las Gallinas Avenue. Walk west on Miller Creek Road about 0.7 mile to Queenstone Road, on the right. Turn right and at the end of the one-block dead-end street, begin hiking uphill on Queenstone Fire Road. View north to Mount BurdellOnce you've climbed to the crest at about 1400 feet, Chicken Shack Fire Road escorts you northeast, eventually ending back at the trailhead. Make sure you bring plenty of water if you choose this route.
     Big Rock Ridge's expansive views are largely wasted in the hot hazy summer season, when you'll sweat mightily traversing the steep fire roads. On clear days in late winter and spring, there are opportunities to gaze across the bay at Mount Diablo and hunt for wildflowers. Regardless of when you visit, Big Rock Ridge, although popular with mountain bikers, is not heavily used, so it's a nice place to hike when you want some solitude (especially on weekdays).
     For the featured hike, start at the Clay Court/Chicken Shack trailhead. Just to the left (but on the same side of the street) of the paved and gated fire road, a paved path heads south. Begin walking on the path, which runs along, at a slight distance, from Alameda del Prado. Coast live oaks and California bays provide partial shade. The path drops down to the street, and becomes a standard sidewalk, meandering through a quiet neighborhood. At 0.49 mile, a thin but sturdy path departs to the right, marked by a generic Pacheco Valle MCOSD sign.Looking back to Big Rock RIdge Ignore this trail and continue along Alameda del Prado to a gated but generally signed fire road at 0.63 mile (just before a "watch out for deer sign"). Turn right onto Little Cat (sometimes called Little Cay) Fire Road and start climbing. (Option: to extend this hike, continue on Alameda del Prado another 0.3 mile, to Curlew Way. Turn right and look for Ponti Fire Road on the right. Ascend on Ponti Fire Road, and at the crest, turn right on Chicken Shack Fire Road. Continue on Chicken Shack back to the trailhead. This will add a little over 2 miles to your hike, and a lot more elevation.)
     Coast live oaks, California bays, valley and black oaks provide partial shade on this wide multi-use trail. Little Cat's initial grade is very harsh, and although the entire trail is steep, there are a few easier stretches and even a short flat bit. As you climb up an arm of the mountain, there are sweeping views of Big Rock Ridge's backbone, the main ridge. A water tank sits on the left side of the trail. Neighborhood noise abates. At 1.12 miles, Little Cat Fire Road ends at a (somewhat) signed junction. Flat stretch of Chicken Shack Fire RoadChicken Shack Fire Road is identified as Big Rock on an old metal sign. Turn right on Chicken Shack Fire Road.
     As the broad fire road, open to hikers, equestrians, and cyclists descends a bit, look to the left for a rough trail and opening in the fenceline. Acres of forested hillside give way to the flatlands of Novato and then the slopes of Mount Burdell. Chicken Shack Fire Road follows just below the contour of the ridgeline, with small blips in elevation. Madrone, oaks, and California bay provide moderate cover, but there's plenty of grassland where you can stop for a lunchtime picnic. This is a quiet section of the preserve, where there are quite a few casual paths and deer trails running near the fire road. At 1.70 miles, unsigned Via Escondido Fire Road departs to the left. Remain on Chicken Shack Fire Road, keeping to the right. Paved portion of Chicken Shack Fire Road
      Chicken Shack Fire Road turns south. Look back over your shoulder for long views to Big Rock Ridge. On a clear day you should be able to see the forested eastern section and the more open grassland portion to the west. Views to the south include San Pedro Mountain and Mount Tamalpais. A sandy trail surface retains footprints of previous human and canine visitors, as well as the deer, bobcat, and coyote that call this ridge home. After a short flat stretch, the trail begins to descend. The water tank on Little Cat Fire Road is visible to the right. Some poison oak, coyote brush, and monkeyflower accompany a tree community comprised mostly of evergreen and deciduous oaks, with madrone, California bay, and a few buckeyes making an appearance as you head downhill. Turning a corner to the east, you'll run smack into a wall of traffic noise from 101. The trail turns to pavement at an open space gate, and you'll pass a water tank fitted with a tennis court top to the right (private property). Keep alert for vehicles as you make your way down the paved trail, which ends back at Alameda del Prado.

Total distance: 2.70 miles
Last hiked: Wednesday, July 18, 2001