The Diablo Range is a

mountain range A mountain range or hill range is a series of mountains or hills arranged in a line and connected by high ground. A mountain system or mountain belt is a group of mountain ranges with similarity in form, structure, and alignment that have arise ...

in the

California Coast Ranges The Coast Ranges of California span from Del Norte or Humboldt County, California, south to Santa Barbara County. The other three coastal California mountain ranges are the Transverse Ranges, Peninsular Ranges and the Klamath Mountains. P ...

subdivision of the

Pacific Coast Ranges The Pacific Coast Ranges (officially gazetted as the Pacific Mountain System in the United States) are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico. Although the ...

in northern

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

, United States. It stretches from the eastern

San Francisco Bay area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...

at its northern end to the

Salinas Valley The Salinas Valley is one of the major valleys and most productive agricultural regions in California. It is located west of the San Joaquin Valley and south of San Francisco Bay and the Santa Clara Valley. The Salinas River, which geologically ...

area at its southern end.

Geography

The Diablo Range extends from the

Carquinez Strait The Carquinez Strait (; Spanish: ''Estrecho de Carquinez'') is a narrow tidal strait in Northern California. It is part of the tidal estuary of the Sacramento and the San Joaquin rivers as they drain into the San Francisco Bay. The strait is ...

in the north to Orchard Peak and Polonio Pass in the south, near the point where State Route 46 crosses over the Coast Ranges at Cholame, as described by the

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

(USGS). It is bordered on the northeast by the

San Joaquin River The San Joaquin River (; es, Río San Joaquín) is the longest river of Central California. The long river starts in the high Sierra Nevada, and flows through the rich agricultural region of the northern San Joaquin Valley before reaching Suis ...

, on the southeast by the

San Joaquin Valley The San Joaquin Valley ( ; es, Valle de San Joaquín) is the area of the Central Valley of the U.S. state of California that lies south of the Sacramento–San Joaquin River Delta and is drained by the San Joaquin River. It comprises seven ...

, on the southwest by the Salinas River, and on the northwest by the

Santa Clara Valley The Santa Clara Valley is a geologic trough in Northern California that extends 90 miles (145 km) south–southeast from San Francisco to Hollister. The longitudinal valley is bordered on the west by the Santa Cruz Mountains and on the east ...

. The USGS designation is somewhat ambiguous north of the Santa Clara Valley, but on USGS maps, the range is shown as the ridgeline which runs between its namesake

Mount Diablo 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 ...

southeastward past Mount Hamilton. Geologically, the range corresponds to the California Coast Ranges east of the

Calaveras Fault The Calaveras Fault is a major branch of the San Andreas Fault System that is located in northern California in the San Francisco Bay Area. Activity on the different segments of the fault includes moderate and large earthquakes as well as aseismi ...

in this northern section. For much of its length, it is paralleled by other sections of the California Coast Ranges to the west, the Santa Cruz Mountains across the southern San Francisco Bay and Santa Clara Valley, and the

Santa Lucia Range The Santa Lucia Mountains (sæntə luˈsiːə) or Santa Lucia Range is a rugged mountain range in coastal central California, running from Carmel southeast for to the Cuyama River in San Luis Obispo County. The range is never more than from ...

across the

. The range passes through Contra Costa,

Alameda An alameda is a Avenue (landscape), street or path lined with trees () and may refer to: Places Canada *Alameda, Saskatchewan, town in Saskatchewan **Grant Devine Dam, formerly ''Alameda Dam'', a dam and reservoir in southern Saskatchewan Chile ...

, San Joaquin, Santa Clara, Stanislaus, Merced, San Benito,

Fresno Fresno () is a major city in the San Joaquin Valley of California, United States. It is the county seat of Fresno County and the largest city in the greater Central Valley region. It covers about and had a population of 542,107 in 2020, maki ...

Monterey Monterey (; es, Monterrey; Ohlone: ) is a city located in Monterey County on the southern edge of Monterey Bay on the U.S. state of California's Central Coast. Founded on June 3, 1770, it functioned as the capital of Alta California under bot ...

, and Kings Counties, and ends in the northwesternmost extremity of

Kern County Kern County is a county located in the U.S. state of California. As of the 2020 census, the population was 909,235. Its county seat is Bakersfield. Kern County comprises the Bakersfield, California, Metropolitan statistical area. The county sp ...

Topography

Though the average elevation is about , a summit of over is considered high, mainly because the range is mostly rolling grassland and plateaus, punctuated by isolated peaks. Plateaus are usually at about . Hills rise to about , while foothills such those in the Santa Clara Valley, Livermore Valley and San Joaquin Valley are typically . Canyons are usually deep; valleys are often deeper but less steep-sided. Peaks often have high topographic prominence, as they are surrounded by valleys or lower hills or plateaus. Streams draining the eastern slopes of the Diablo Range include

Hospital Creek Hospital Creek, originally Arroyo de Ospital, or Arroyo del Osnital is a tributary of the San Joaquin River draining eastern slopes of a part of the Diablo Range within San Joaquin County. The creek is approximately long,U.S. Geological Survey. ...

and

Ingram Creek Ingram Creek, originally Arroyo de la Suerte, is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map , accessed March 11, 2011 tributary of the San Joaquin River in Stanislaus County, in the San Joaqu ...

. Stream draining the western slopes include Alameda Creek and Coyote Creek.

Peaks

The Diablo Range's peaks and ridges are between and are distinct landmarks.

(), San Benito Mountain (), Mount Hamilton Ridge (), and Mount Stakes () are four of the highest peaks in the range.

Human elements

The Diablo Range is paralleled for much of its distance by U.S. Route 101 to the west and by

I-5 Interstate 5 (I-5) is the main north–south Interstate Highway on the West Coast of the United States, running largely parallel to the Pacific coast of the contiguous U.S. from Mexico to Canada. It travels through the states of Californi ...

to the east. Major routes of travel through the range include: * North of the range ** BNSF Railway/ Amtrak San Joaquin * Willow Pass ** State Route 4 **

BART Bart is a masculine given name, usually a diminutive of Bartholomew, sometimes of Barton, Bartolomeo, etc. Bart is a Dutch and Ashkenazi Jewish surname, and derives from the name ''Bartholomäus'', a German form of the biblical name ''Bartho ...

* Altamont Pass **

Union Pacific Railroad The Union Pacific Railroad , legally Union Pacific Railroad Company and often called simply Union Pacific, is a freight-hauling railroad that operates 8,300 locomotives over routes in 23 U.S. states west of Chicago and New Orleans. Union Paci ...

/ Altamont Corridor Express ** I-580 *

Sunol Valley Sunol Valley ( es, Valle de Suñol) is located in Alameda County, California, United States. The small town of Sunol lies in the valley. It is largely rural, but is in proximity to the highly populated Bay Area suburbs of Fremont, Pleasanton, ...

** State Route 84 ** I-680 * Patterson Pass *

Corral Hollow Pass Corral Hollow Pass, originally Portezuela de Buenos Ayres (Pass of Good Winds) is a low mountain pass in the Diablo Range southeast of Livermore, in Alameda County, California. This pass, at an elevation of 1600 ft, was the point where El Cami ...

* Mount Hamilton ** State Route 130 *

Pacheco Pass Pacheco Pass, elevation , is a low mountain pass located in the Diablo Range in southeastern Santa Clara County, California. It is the main route through the hills separating the Santa Clara Valley and the Central Valley. As with most passes in ...

** State Route 152 ** Future

California High-Speed Rail California High-Speed Rail (also known as CAHSR or CHSR) is a publicly funded high-speed rail system currently under construction in California in the United States. Planning for the project began in 1996, when the California Legislature and Gover ...

* Panoche Pass * State Route 198 * Cottonwood Pass (

State Route 41 The following highways are numbered 41: International * AH41, Asian Highway 41 * European route E41 Australia * Olympic Highway * Mid-Western Highway Canada * Alberta Highway 41 * British Columbia Highway 41 * Manitoba Highway 41 * Newfoundlan ...

) * Polonio Pass ( State Route 46) A sparsely used gravel road is the highest road in the range, with its highest point being on San Benito Mountain at over 5,000 feet. The Diablo Range is largely unpopulated outside of the

San Francisco Bay Area The San Francisco Bay Area, often referred to as simply the Bay Area, is a populous region surrounding the San Francisco, San Pablo, and Suisun Bay estuaries in Northern California. The Bay Area is defined by the Association of Bay Area Go ...

. Major nearby communities include,

Antioch Antioch on the Orontes (; grc-gre, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου, ''Antiókheia hē epì Oróntou'', Learned ; also Syrian Antioch) grc-koi, Ἀντιόχεια ἡ ἐπὶ Ὀρόντου; or Ἀντιόχεια ἡ ἐπ� ...

, Pittsburg,

Concord Concord may refer to: Meaning "agreement" * Pact or treaty, frequently between nations (indicating a condition of harmony) * Harmony, in music * Agreement (linguistics), a change in the form of a word depending on grammatical features of other ...

Walnut Creek A walnut is the edible seed of a drupe of any tree of the genus ''Juglans'' (family Juglandaceae), particularly the Persian or English walnut, ''Juglans regia''. Although culinarily considered a "nut" and used as such, it is not a true bo ...

, Alamo, Danville, San Ramon, Pleasanton, Livermore, Fremont,

Milpitas Milpitas (Spanish for "little milpas") is a city in Santa Clara County, California, in Silicon Valley. As of the 2020 census, the city population was 80,273. The city's origins lie in Rancho Milpitas, granted to Californio ranchero José Marí ...

, San Jose, Morgan Hill, and Gilroy and the Central Valley city of Tracy. South of Pacheco Pass, the only major nearby communities (those with a population over 15,000) are Los Banos, and Hollister. The small town of

Coalinga Coalinga ( or ) is a city in Fresno County and the western San Joaquin Valley, in central California about 80 miles (128 km) southeast of Salinas. It was formerly known as ''Coaling Station A'', ''Coalingo'', and ''Coalinga Station''. Th ...

may also be notable for its location on State Route 198, one of the few routes through the mountains. Also the town of

Kettleman City Kettleman City is a census-designated place (CDP) in Kings County, California, United States. Kettleman City is located southwest of Hanford, 54 miles (88 km) south of Fresno, at an elevation of , and sits only about 1/2 mile north of the 36th p ...

is also on State Route 41, another route that crosses the mountains. Towns west of the range south of Gilroy include: Salinas, King City, and Paso Robles.

Protected areas

Most of the range consists of private ranchland, limiting recreational use. However, the range does contain several areas of parkland, including

Mount Diablo State Park Mount is often used as part of the name of specific mountains, e.g. Mount Everest. Mount or Mounts may also refer to: Places * Mount, Cornwall, a village in Warleggan parish, England * Mount, Perranzabuloe, a hamlet in Perranzabuloe parish, C ...

Alum Rock Park Alum Rock Park, in the Alum Rock district of San Jose, California, is California's oldest municipal park, established in 1872 but serving as public land since the pueblo was established in 1777. Located in a valley in the Diablo Range foothills ...

, Grant Ranch Park, Henry W. Coe State Park, Laguna Mountain Recreation Area, and the BLM's Clear Creek Management Area. In addition, some private land is held in

conservation easement In the United States, a conservation easement (also called conservation covenant, conservation restriction or conservation servitude) is a power invested in a qualified private land conservation organization (often called a "land trust") or gover ...

s by the California Rangeland Trust.

Natural history

Since the range lies around inland from the ocean, and other coastal ranges like the

and the Santa Cruz Mountains block incoming moisture, the range gets little precipitation. In addition, the average elevation of is not high enough to catch most of the incoming moisture at higher altitudes. Winters are mild with moderate rainfall, but summers are very dry and hot. Areas above 2,500 feet (762 m) get light to moderate snow in the winter, especially at the highest point, the 5,241 ft (1,597 m) San Benito Mountain in the remote southeastern section of the range. However, though sites at the lower end get annual snowfall, it is typically light and melts too fast to be noticed. Once or twice a decade there is seriously deep and long lasting snowfall. Mercury contamination near the southern end of the range is an ongoing problem, due to the New Idria quicksilver mines, which stopped production in the 1970s. Heavy mercury contamination has been documented in the San Carlos and Silver Creeks, which flow into Panoche Creek, and thence into the

. This has resulted in mercury contamination all the way downstream to the San Francisco Bay. Silver and San Carlos creeks provide a wetland environment in an otherwise arid region and are important for the ecology of the region. As of 2011, New Idria has been listed as a Superfund site and scheduled for cleanup.

Flora

The Diablo Range is part of the

California interior chaparral and woodlands The California interior chaparral and woodlands ecoregion covers in an elliptical ring around the California Central Valley. It occurs on hills and mountains ranging from to . It is part of the Mediterranean forests, woodlands, and scrub biome, ...

ecoregion An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of ...

. It is covered mostly by chaparral and

California oak woodland California oak woodland is a plant community found throughout the California chaparral and woodlands ecoregion of California in the United States and northwestern Baja California in Mexico. Oak woodland is widespread at lower elevations in coastal ...

communities, with stands of closed-cone pine forests appearing above 4,000 feet (1,219 m). The native bunch grass

savanna A savanna or savannah is a mixed woodland- grassland (i.e. grassy woodland) ecosystem characterised by the trees being sufficiently widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to ...

has been predominantly replaced by annual Mediterranean grasses, except in some rare

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

fragments. The understory is dominated with nonnative invasives. Blooming in spring are such plants as ''

Viola pedunculata ''Viola pedunculata'', the California golden violet, Johnny jump up, or yellow pansy, is a perennial yellow wildflower of the coast and coastal ranges in California and northwestern Baja California. The common name "Johnny jump up" is usually ...

'', '' Dodecatheon pulchellum'', ''

Fritillaria liliacea ''Fritillaria liliacea'', the fragrant fritillary, is a threatened bulbous herbaceous perennial plant in the lily family Liliaceae. It is native to the region surrounding San Francisco Bay in California, USA. Description The bell-shaped white ...

'', and '' Ribes malvaceum'', which can be viewed in the

Blue Oak Ranch Reserve The Blue Oak Ranch Reserve, a unit of the University of California Natural Reserve System, is an ecological reserve and biological field station in Santa Clara County, California. It is located on in the Diablo Range, northwest of Mount Hamilt ...

. The range's

riparian zone A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks a ...

s have such trees as

bigleaf maple ''Acer macrophyllum'', the bigleaf maple or Oregon maple, is a large deciduous tree in the genus '' Acer''. It is native to western North America, mostly near the Pacific coast, from southernmost Alaska to southern California. Some stands are al ...

(''Acer macrophyllum''), white alder (''Alnus rhombifolia''), California bay (''Umbellularia californica''), and California sycamore (''Platanus racemosa''). The most common trees are

coast live oak ''Quercus agrifolia'', the California live oak, or coast live oak, is a highly variable, often evergreen oak tree, a type of live oak, native to the California Floristic Province. It may be shrubby, depending on age and growing location, but is ...

(''Quercus agrifolia'') and blue oak (''Quercus douglasii''), with the largest blue oak growing in Alameda County. There are also good populations of California buckeye (''Aesculus californica''), and California black oak (''Quercus kelloggii''). The

gray pine ''Pinus sabiniana'' (sometimes spelled ''P. sabineana''), with vernacular names including towani pine, foothill pine, gray pine, bull pine, and digger pine, is a pine endemic to California in the United States. Some sources discourage using the n ...

(''Pinus sabiniana'') and rarer

Coulter pine The Coulter pine or big-cone pine, ''Pinus coulteri'', is a native of the coastal mountains of Southern California in the United States and northern Baja California in Mexico. Isolated groves are found as far north as Clearlake, California on the ...

(''Pinus coulteri'') can be found at all elevations, especially between . Coulter pine reaches its northern limit on northern of Mt. Diablo. The conifers at higher elevations in the Diablo Range include knobcone pine (''Pinus attenuata''), Jeffrey pine (''Pinus jeffreyi'') and

ponderosa pine ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is the ...

(''Pinus ponderosa'').

Fauna

The Diablo Range attracts far more raptors than coastal forests, such as

red-tailed hawk The red-tailed hawk (''Buteo jamaicensis'') is a bird of prey that breeds throughout most of North America, from the interior of Alaska and northern Canada to as far south as Panama and the West Indies. It is one of the most common members wit ...

Golden eagle The golden eagle (''Aquila chrysaetos'') is a bird of prey living in the Northern Hemisphere. It is the most widely distributed species of eagle. Like all eagles, it belongs to the family Accipitridae. They are one of the best-known birds of ...

nesting sites are found in the Diablo Range, reaching their highest density in southern Alameda County. The Bay checkerspot butterfly, a federally listed

threatened species Threatened species are any species (including animals, plants and fungi) which are vulnerable to endangerment in the near future. Species that are threatened are sometimes characterised by the population dynamics measure of '' critical depen ...

, has habitat in the Range, especially at Mount Diablo. The

California tiger salamander The California tiger salamander (''Ambystoma californiense'') is a vulnerable amphibian native to California. It is a mole salamander. Previously considered to be a subspecies of the tiger salamander (''A. tigrinum)'', the California tiger sal ...

(''Ambystoma californiense''), also a federally threatened species and a

vulnerable species A vulnerable species is a species which has been categorized by the International Union for Conservation of Nature as being threatened with extinction unless the circumstances that are threatening its survival and reproduction improve. Vulnera ...

of amphibian native to Northern California, lives in ponds in the range. The northern Pacific rattlesnake is thriving, as are many

ground squirrel Ground squirrels are members of the squirrel family of rodents ( Sciuridae), which generally live on or in the ground, rather than trees. The term is most often used for the medium-sized ground squirrels, as the larger ones are more commonly known ...

hares Hares and jackrabbits are mammals belonging to the genus ''Lepus''. They are herbivores, and live solitarily or in pairs. They nest in slight depressions called forms, and their young are able to fend for themselves shortly after birth. The gen ...

, and various species of native and nonnative rodents.

Tule elk The tule elk (''Cervus canadensis nannodes'') is a subspecies of elk found only in California, ranging from the grasslands and marshlands of the Central Valley to the grassy hills on the coast. The subspecies name derives from the tule (), a ...

(''Cervus canadensis ssp. nannodes'') were restored to Mount Hamilton between 1978-1981 and are slowly recovering in several small herds in Santa Clara and Alameda Counties. See Mount Hamilton elk recovery.

Black-tailed deer Two forms of black-tailed deer or blacktail deer that occupy coastal woodlands in the Pacific Northwest of North America are subspecies of the mule deer (''Odocoileus hemionus''). They have sometimes been treated as a species, but virtually all r ...

are abundant.

Pronghorn The pronghorn (, ) (''Antilocapra americana'') is a species of artiodactyl (even-toed, hoofed) mammal indigenous to interior western and central North America. Though not an antelope, it is known colloquially in North America as the American a ...

, grizzly bears, and

wolves The wolf (''Canis lupus''; : wolves), also known as the gray wolf or grey wolf, is a large canine native to Eurasia and North America. More than thirty subspecies of ''Canis lupus'' have been recognized, and gray wolves, as popularly un ...

were extirpated in the 1800s. There still are numerous

coyotes The coyote (''Canis latrans'') is a species of canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecological nich ...

and some of the more vital

mountain lion The cougar (''Puma concolor'') is a large cat native to the Americas. Its range spans from the Canadian Yukon to the southern Andes in South America and is the most widespread of any large wild terrestrial mammal in the Western Hemisphere. ...

populations in the state. There are excellent populations of bobcats and

gray fox The gray fox (''Urocyon cinereoargenteus''), or grey fox, is an omnivorous mammal of the family Canidae, widespread throughout North America and Central America. This species and its only congener, the diminutive island fox (''Urocyon littor ...

es, which depend on the chaparral habitat. A species of millipede, ''

Illacme plenipes ''Illacme plenipes'' is a siphonorhinid millipede found in the central region of the U.S. state of California. It has up to 750 legs. One of two known species in the genus ''Illacme'', it was first seen in 1926, but was not rediscovered until ...

'', is endemic to the southern Diablo Range. First described in 1926, then not seen again until 2005, the species has more legs than any other species of millipede, with one specimen having 750.666-Legged Creature Rediscovered
LiveScience (2006-06-07). Retrieved on 2013-07-21.

References