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Coal Mine Ridge Nature Preserve comprises the 235 acre, northwestern section of Coal Mine Ridge Open Space. In 1975 as part of the development of Portola Valley Ranch the developer signed an agreement to preserve this land as open space in perpetuity and grant trail easements to the Town so that the general public could enjoy its natural tranquility and beauty.


The original stewards of the ridge were the indigenous Muwekma Ohlone people. They relied on a close relationship with the land, observing the natural world around them as they gathered and harvested. They could be called the quintessential naturalists, passing on their knowledge through oral tradition, learning by doing, and teaching by example. Much has changed since then.  The Coal Mine Ridge that you see today, bordered by Los Trancos and Corte Madera Creeks, takes its name from the 19th century search for minerals. However, the only coal found here was poor in quality, and a major landslide in 1890 buried the mine beyond recovery.

Except for the historic Old Spanish Trail, the trails in this nature preserve were created as part of the construction of Portola Valley Ranch, and today all of the trails are maintained by the Town of Portola Valley. Toyon Trail was built by volunteers, including many town residents, and designed by town naturalist Herb Dengler. He gave it a gentle grade, winding it through trees and providing multiple vistas without a strenuous climb.

Depicted here are a few of the animals and plants you may see in Coal Mine Ridge Nature Preserve. The wildlife, flowers, grasses, ferns and other plants you see on the preserve will change according to season. Look, listen, smell, but don’t touch; you will discover many on your own.

DOGS AND BICYCLES ARE NOT PERMITTED ANYWHERE INSIDE THE NATURE PRESERVE. Research shows that birds and many animal species perceive dogs as predators, and feeling threatened, will leave the area, often permanently. Likewise, these trails were not designed to accommodate the speed and motion of bicycles, which can lead to erosion, bring in pathogens that affect the native flora, and present a danger to hikers and equestrians. Please consult the map for nearby trails that do permit dogs and bikes.

While hiking these trails, you may observe a wide variety of native flora and fauna. Seasonal ferns, wild-flowers, grasses, and shrubs cover the landscape. Some blue, black, and valley oaks are more than a century old, and ancient California live oaks still stand here, having survived both timber cutters and Sudden Oak Death. You may also notice a range of birds and other animals. Some, such as the more elusive bobcat, coyote, and puma (mountain lion), are here even though you may not see them. Because all of these species are fragile, HIKERS ARE REQUIRED TO STAY ON DESIGNATED TRAILS AT ALL TIMES.

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