Mount Diablo is a mountain of the Diablo Range, in Contra Costa County of the eastern San Francisco Bay Area in Northern California. It is south of Clayton and northeast of Danville. It is an isolated upthrust peak of , visible from most of the San Francisco Bay Area. Mount Diablo appears from many angles to be a double pyramid and has many subsidiary peaks. The largest and closest is North Peak, the other half of the double pyramid, which is nearly as high in elevation at , and is about northeast of the main summit.
The mountain is within the boundaries of Mount Diablo State Park, which is administered by California State Parks.
Geography
The summit is accessible by foot, bicycle, or motor vehicle. Road access is via North Gate Road or South Gate Road.
Mount Diablo State Park
The peak is in Mount Diablo State Park, a state park of about . The state park was the first public open space established on or near the peak. According to the non-profit Save Mount Diablo, there are now varied types of protected lands on and around Mount Diablo that total more than . These include 38 preserves, such as nearby city open spaces, regional parks, and watersheds, which are buffered in some areas with private lands that have been protected by conservation easements.
Viewshed
On a clear day, the Sierra Nevada range is plainly visible from the summit. The best views are after a winter storm; a snowy Sierra shows up better, and summer days are likely to be hazy. Lassen Peak, away, is occasionally just visible over the curve of the earth. Sentinel Dome in Yosemite National Park is visible, but Half Dome is hidden by the 8000-foot ridge at 37.755N 119.6657W. Eight bridges are visible, from left to right (southwest to northeast): San Mateo, Bay, Golden Gate, San Rafael, Carquinez, Benicia, Antioch, and Rio Vista.
Many peaks in the state are taller, but Mount Diablo has a remarkable visual prominence for a mountain of such low elevation. Its looming presence over much of the Bay Area, delta, and Central Valley, and good visibility even from the Mother Lode, all key regions during the gold rush and early statehood, made it an important landmark for mapping and navigation. The summit is used as the reference datum for land surveying in much of northern California and Nevada.
It boasts one of the largest viewsheds in the Western United States and played a key role in California history.
Cultural history
Mount Diablo is sacred to many California Native American peoples. According to Miwok mythology and Ohlone mythology, it was the point of creation. The local peoples of the area traditionally had a variety of creation narratives associated with the mountain. In one surviving narrative fragment, Mount Diablo and Reed's Peak (Mount Tamalpais) were surrounded by water; from these two islands the creator Coyote and his assistant Eagle-man made Native American people and the world. In another, Molok the Condor brought forth his grandson Wek-Wek the Falcon Hero, from within the mountain.
Earliest names About 25 independent tribal groups with well-defined territories lived in the East Bay countryside surrounding the mountain at time of European contact. Their members spoke dialects of three distinct languages: Ohlone, Bay Miwok, and Northern Valley Yokuts.Milliken, Randall, (2008) Native Americans at Mission San Jose, 2008, Malki-Ballena Press. The Chochenyo-speaking Ohlone from Mission San Jose and the East Bay area, call the mountain , meaning "at the dawn of time". Further inland, the Nisenan of the Sacramento Valley call it , "dog mountain"; because, as Nisenan elder Dalbert Castro once explained, it's "the place where dogs came from in trade".http://www.savemountdiablo.org/why_mtdiablohistory.html A Southern Sierra Miwok name for the mountain is , and a Northern Sierra Miwok name is .
It has also been suggested that another early Native American name for the mountain was or , but there is no evidence to confirm the assertion. According to Indian historian Bev Ortiz and Save Mount Diablo: "The name was made up in 1866 — with no real Native American connection — referred to the California Legislature's Committee on Public Morals, and tabled. It resurfaced as a real estate gimmick in 1916 with a supposed new translation, "Laughing Mountain", attributed without documentation to Diablo area Volvon Indians. explains the mountain's naming and debunks the name "Kahwookum" as fictitious.
Most of Mount Diablo, including its peak, was within the homeland of the early Volvon (sometimes spelled Wolwon, Bolbon or Bolgon), a Bay Miwok–speaking tribe. As early as 1811, Spanish colonists referred to the mountain as ("High Hill of the Volvon") or sometimes .
Current name The conventional view is that the peak derives its name from the reaction of Spanish soldiers to the 1805 escape of several Chupcan Native Americans in a willow thicket some north of the mountain. One story tells that their nighttime escape through the thicket was aided by mysterious lights. An 1850 report by General Mariano G. Vallejo tells of a strange dancing spirit turning the battle in favor of the Chupcan. Vallejo interpreted the natives' word for the personage, , to mean "devil" in the Anglo-American language.Hulaniski 1917, Chapter XIV Mount Diablo; for one interpretation of the context of the Spanish attack on the Chupcan, see Milliken, Randall, (1995) A Time of Little Choice: The Disintegration of Tribal Culture in the San Francisco Bay Area, 1769-1810, Menlo Park, California: Ballena Press, pp.184-185, 241 Vallejo's report could be interpreted to align with Edward G. Gudde's history of place names. (Kyle, and Ortiz)
By 1824, the region north of the mountain came to be known as Monte del Diablo () meaning "devil's thicket." In this case monte should be translated as thicket or dense woods. It was shown on maps near present-day Concord (formerly known as Pacheco).Plano topografico de la Misión de San José Later, U.S. settlers understood "Monte" to refer directly to the mountain, and it was recorded with varying degrees of certainty until "Mount Diablo" became official in 1850.
In May 1862, California Geological Survey field director William H. Brewer named the northeast peak of Mount Diablo "Mount King", after Rev. Thomas Starr King, a Unitarian clergyman, abolitionist, Republican, Yosemite advocate, cultural Unionist, and California's leading intellectual. Today it is known as North Peak.
Early uses In 1851 the south peak of the mountain was selected by Colonel Leander Ransom as the initial point—where the Mount Diablo Base and Mount Diablo Meridian lines intersect—for cadastral surveys of a large area. Subsequent surveys in much of California, Nevada and Oregon were located with reference to this point.
Toll roads up the mountain were created in 1874 by Joseph Seavey Hall and William Camron (sometimes "Cameron"); Hall's Mount Diablo Summit Road was officially opened on May 2, 1874. Camron's "Green Valley" road opened later. Hall also built the 16-room Mountain House Hotel near the junction of the two roads, a mile below the summit (2,500 foot elevation. (It operated through the 1880s, was abandoned in 1895, and burned c. 1901). As far north as Meridian Road, on the outskirts of Chico, California, the summit was used as a reference point. The road is colinear with the summit, and is named for the meridian which intersects it.
An aerial navigation beacon, the Standard Diablo tower, was erected by Standard Oil at the summit in 1928. The 10-million-candlepower beaconA Standard ad (Aviation Week, October 30, 1961, p14) depicts a focused beam, unlike the present light. became known as the "Eye of Diablo" and was visible for a hundred miles. From 1954–1957, Mount Diablo was used for broadcasting purposes by radio station KSBR-FM and television station KOVR (channel 13, Stockton).
Protection of the area
After initial legislation in 1921, the state of California acquired enough land in 1931 to create a small state park around the peak. Many improvements were carried out in the 1930s by the Civilian Conservation Corps, but park expansion slowed in the 1940s through the 1960s.
Significantly, botanist Mary Leolin Bowerman (1908–2005), founder of the Save Mount Diablo non-profit in 1971, published her Ph.D. dissertation in 1936 at the University of California, Berkeley. In 1944 she published her book, The Flowering Plants and Ferns of Mount Diablo, California. Her study boundaries became the basis for the state park's first map and for the park's eventual expansion. Her work also became the origin of many of the park's place names.
This state park has been greatly expanded over the decades. Soon after Earth Day in 1971, the nonprofit organization "Save Mount Diablo" was created by co-founders Mary Bowerman and Art Bonwell, barely ahead of real estate developers. At the time, the state park included just and was the only park in the vicinity of the mountain. In 2007 the state park totaled almost , and with 38 parks and preserves on and around the mountain, Diablo's public lands total more than . According to Save Mount Diablo, there are 50 individual preserves on and around Mount Diablo, some of which are conservation easements covering a single parcel, others are expected to eventually be absorbed into larger nearby parks. As of December 2007, the organization recognizes 38 specific Diablo parks and preserves.
The State Park adjoins park lands of the East Bay Regional Park District, including Morgan Territory Regional Preserve, Brushy Peak Regional Preserve, Vasco Caves Regional Preserve, and Round Valley Regional Preserve. It also adjoins protected areas owned or controlled by local cities such as the Borges Ranch Historic Farm, the Concord Naval Weapons Station (now in the process of being converted to non military use), Indian Valley, Shell Ridge Open Space and Lime Ridge Open Spaces near the city of Walnut Creek, and east to the Los Vaqueros Reservoir watershed. The new Marsh Creek State Park and Black Diamond Mines Regional Preserve are among the open spaces stretching to the north. In this way the open spaces controlled by cities, the East Bay Regional Park District, Mount Diablo State Park, and various regional preserves now adjoin and protect much of the elevated regions of the mountain. There are unprotected areas in Arroyo del Cerro, Curry Canyon, the Marsh creek region, and on the northern slopes of North Peak, and in a number of inholdings surrounded by preserve land.
Park expansion continues on all sides of the mountain although its western boundaries are largely complete. Extensive development continues in the southwestern foothills and Tassajara region, such as the upscale development of Blackhawk and individual estates overlooking the Livermore Valley on Morgan Territory Road. Other large projects are proposed in the northern Black Diamond Mines and Los Medanos foothills, at the Concord Naval Weapons Station, and near Marsh Creek State Park. Large-scale development of other private parcels is restricted by city and county urban limit lines, by lack of water, excessive slope, and sensitive resources including rare species. Development of smaller ranchette subdivisions continue to fragment and threaten many parcels and large areas of habitat.
In 2007, Save Mount Diablo published Mount Diablo, Los Vaqueros & Surrounding Parks, Featuring the Diablo Trail, documenting Mount Diablo's more than of protected lands. It includes 100 access points, of trail, and of private fire roads.
Natural history
Geology There are three major groups of rocks composing Mount Diablo -- the Mount Diablo Ophiolite group, dating to the Jurassic; the Franciscan Complex, dating to the Jurassic and Cretaceous; and the combination of the Great Valley Group (Jurassic and Cretaceous) and Younger Sedimentary rocks (Cenozoic).