Marin County Parks and Open Space Department

This huge property (1500 acres) is a wild and rugged place. One can’t help but get a sense of true wilderness when walking along the San Geronimo Ridge Fire Road that traverses the ridgeline. On the other side of this ridge, the Marin Municipal Water District (MMWD) watershed lands above Kent Lake form an immense expanse of pristine forests stretching all the way to Mount Tamalpais. The windswept ridge has a high altitude feel, accentuated by the presence of a forest of dwarf Sargent Cypress trees. Interspersed along the way are patches of the rare Marin Manzanita, and in the rock gardens between the shrubs are lovely jewel flowers and other delicate blooms in abundance.

This area was once slated for development. Considerable local support for its preservation resulted in its acquisition by MCOSD. The preserve was named in honor of Gary Giacomini, a long-time west Marin county board of supervisor who was instrumental in orchestrating the deal that saved this land from development. Recently, the lush redwood canyon formerly known as Bates Canyon was renamed to honor Willis Evans, a tireless environmental advocate who spearheaded local efforts to preserve coastal streams.

Gary Giacomini DetailNearly five miles of the San Geronimo Fire Road run along the southern boundary of this preserve. This road, extending from Peter’s Dam (at the Shafter bridge crossing on Sir Francis Drake Boulevard) to Azalea Hill on the Bolinas-Fairfax Road, is among the most scenic (and longest) fire roads in Marin. Hikers, bicyclists, and equestrians wishing to link together longer outings should consider exploring this road that connects with our White’s Hill and Cascade Canyon preserves, as well as many popular trails and roads in the MMWD watershed.

To protect sensitive wildlife species, some trails in Gary Giacomini Preserve are subject to seasonal night closures. Please observe trail closure signs.


From Hwy 101 in Larkspur, take the exit for Sir Francis Drake Blvd west 7.7 miles. Turn left onto Railroad Ave, sharp right onto San Geronimo Valley Dr, and take the second left onto Redwood Canyon Dr. The gate is immediately on the right.

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

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Birds, Geologic Interest, Horse Trough, Redwoods, Wildflowers


February to July: Some roads and trails subject to night closure – August to January: 24 hours

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