Marin County Parks and Open Space Department

Lucas Valley DetailThis 1271 acre preserve includes much of the south-facing slope rising above what is now known as Lucas Valley (historically called Gallinas Valley). The highlight of this preserve is the Big Rock Trail, a multiple-use trail that begins at the crest of Lucas Valley Road (at the ”Big Rock”), and eases its way up to the Big Rock Ridge Fire Road. This trail, opened in 2003, is part of the Bay Area Ridge Trail. It connects with the Loma Alta Trail that ascends the southern half of the valley. Portions of both the Big Rock Trail and the fire road along the ridge are trail easements that cross private property, so pay heed to all trail signs posted along the way. The summit of Big Rock Ridge at 1895 feet is the second highest point in Marin County (after Mount Tamalpais), and views from the top are spectacular. An alternate route between the valley floor and the ridge is the incredibly steep Luiz Fire Road, but one trip up (or down) this old road will make you truly appreciate the new trail for its beauty and gentle grade.


From Hwy 101 in San Rafael, take the exit for Lucas Valley Rd west approximately 5.5 miles (look for the big rock). The trailhead is on the north side of Lucas Valley Rd.

Visit,,, or dial 511 to find out about alternative transportation and public transit options from your location.

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Birds, Horse Trough, Wildflowers


24 hours

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