This range of mountains along the California coast stretches for just over 100 miles from just south of the City of San Francisco in the northwest to just north of the City of Monterey, California, in the southeast. The range separates the southern section of the San Francisco Bay area from the Pacific Ocean and rises from just above sea level to near 4,000 feet elevation in some sections.

The area now occupied by the San Cruz Mountains was, in pre-hisortic time, the entrance to a vast inland sea that encompassed central California’s San Joaquin Valley. These mountains lie on a large section of land known as the “Salinian Block” and are atop the junction between the Continental plate and Pacific plate sections of the earth’s surface. Over a period of from one to two million years, by a process called subduction, the Continental plate has forced itself beneath the Pacific plate. This process has progressively forced the edge of the Pacific plate upward, forming the Santa Cruz Mountains. Unlike the other, older Pacific mountain ranges, these mountains are very young and are made up mostly of sedimentary rock, known as sandstone, which is very prone to movement. Solid rock ledges and faces generally only populate sections of the upper elevations of the mountains. They were pushed up from the sea floor in the early stage of subduction.

Northwesterly movement of the Pacific plate at a rate of one to two inches a year along its junction with the Continental plate has resulted over time in a series of fractures in the Salinian Block. These fractures form what is commonly known as the “San Andreas Fault System” and include, along with the “San Andreas Fault”, other faults such as the “Zayante Fault.” It is this Zayante Fault that precipitated the “1989 Loma Prieta Earthquake” that badly damaged sections of the San Francisco Bay area and coastal cities along these mountains.

From pre-historic time, these mountains have been populated with gigantic California Coastal Redwoods, a.k.a., “Sequoia Sempervirens.” In more recent time, these mountains were heavily logged for redwood lumber to build the City of San Francisco, surrounding cities and towns, and other infrastructure, during the “California Gold Rush.” Currently, the mountains are populated with old-growth, 2nd growth and 3rd growth Redwood, Douglas Fir, Madrone, Sycamore, Red Alder, Big-Leaf Maple, Cottonwood and various varieties of Oak. The mountains also host twelve varieties of Fern and may other species of flora.

The fauna of the mountains include Stellar Jays, Red-Tail Hawks, Acorn Woodpeckers, Owls, Salamanders, Millipede, Newts, Banana Slugs, Frogs, Raccoons, Deer, Squirrels, Skunks, Rabbits, Opossums, wild Pigs, Coyotes, Bob Cats and Mountain Lions. Bear have not been present since the early 20th Century.

For day-hikers and back-packers, there are hundreds of miles of maintained single-track trail and fire roads, a temperate climate and eleven “for-fee” trail camps.