Big Rock Ridge is a
ridge
A ridge is a long, narrow, elevated geomorphologic landform, structural feature, or a combination of both separated from the surrounding terrain by steep sides. The sides of a ridge slope away from a narrow top, the crest or ridgecrest, wi ...
near
Novato, California
Novato (Spanish language, Spanish for "Novatus") is a city in Marin County, California, United States, situated in the North Bay (San Francisco Bay Area), North Bay region of the San Francisco Bay Area. At the 2020 United States census, 2020 c ...
, and the 2nd tallest point in
Marin County
Marin County ( ) is a county located in the northwestern part of the San Francisco Bay Area of the U.S. state of California. As of the 2020 census, the population was 262,231. Its county seat and largest city is San Rafael. Marin County is ac ...
. The ridge is 5 miles long, and runs from the northwest to the east, dividing Novato's Ignacio Valley and San Rafael's Lucas Valley, and separating Novato from central and southern Marin County.
Big Rock Ridge is named after the rock at the base of Big Rock Trail.
Geography
Big Rock Ridge is the second-highest point in the
Marin Hills
The Marin Hills are a series of steep high ridges and peaks in southern Marin County. They are a part of the long Pacific Coast Ranges mountain system. The centerpoint of these hills is the 2,571 foot (784 m) Mount Tamalpais near Mill Valley. T ...
, which in turn are a part of the
California Coast Ranges
The Coast Ranges of California span from Del Norte County, California, Del Norte or Humboldt County, California, south to Santa Barbara County, California, Santa Barbara County. The other three coastal California mountain ranges are the Trans ...
. Much of eastern Big Rock Ridge is public land, with the Lucas Valley and Ignacio Open Space Preserves covering much of the foothills. Much of the eastern side also falls within city limits, with the northeastern side being in
Novato
Novato (Spanish for "Novatus") is a city in Marin County, California, United States, situated in the North Bay region of the San Francisco Bay Area. At the 2020 census, Novato had a population of 53,225.
History
What is now Novato was origi ...
and the southeastern side falling within
Lucas Valley-Marinwood.
Various trails run up the ridge, but they all converge at the Big Rock Ridge Fire Road, which runs along the top of the ridge to access the 2 radio towers at the top.
The easiest way to the top is the 6.7 mile Big Rock Trail, which opened in 2003 when
George Lucas
George Walton Lucas Jr. (born May 14, 1944) is an American filmmaker and philanthropist. He created the ''Star Wars'' and ''Indiana Jones'' franchises and founded Lucasfilm, LucasArts, Industrial Light & Magic and THX. He served as chairman ...
donated 800 acres of land to create the Lucas Valley Open Space Preserve. The views from Big Rock Ridge are sweeping, with views to
Mt. St Helena and
Mt. Diablo from the top.
Geology
Much of the soil on the northern slope is Tocaloma-McMullen Complex soil, which is mostly gravelly loam with a medium to high runoff class. With a land capability classification of 7e and extremely steep slopes, most of the land is unsuitable for cultivation. The southern slope is much more varied when it comes to soil types, but they all share a high runoff class and a land capability classification of 7e. Nearly all of the soil on the north slope is extremely prone to runoff, and is in Hydrologic Soil Group D. The south slope is more mixed.
Hydrology
Many creeks start on Big Rock Ridge.
Miller Creek, Ignacio Creek, Halleck Creek, Arroyo San Jose, Arroyo Avichi,, Pacheco Creek, and Blackstone Creek all start on Big Rock Ridge.
[{{Cite web , title=Miller Creek watershed map , url=https://marinflooddistrict.org/documents/miller-creek-watershed-map/ , access-date=2023-10-05 , website=Marin County Flood Control District , language=en-US]
Novato, California