Peninsular Ranges

The Peninsular Ranges (also called the Lower California province[1]) are a group of mountain ranges that stretch 1,500 km (930 mi) from Southern California to the southern tip of the Baja California Peninsula; they are part of the North American Coast Ranges, which run along the Pacific Coast from Alaska to Mexico. Elevations range from 500 to 10,834 feet (152 to 3,302 m).

Peninsular Ranges
Devils-Peak Sierra-SanPedroMartir BajaCalifornia Mexico
Sierra San Pedro Mártir and Devils Peak, Southern Baja California, Mexico
Highest point
PeakSan Jacinto Peak
Elevation10,834 ft (3,302 m)
CountriesMexico and United States
StatesBaja California Sur, Baja California and California
Age of rockMesozoic
Type of rockGranite


The Peninsular Ranges include the Santa Ana Mountains, Temescal and other mountains and ranges of the Perris Block, San Jacinto and Laguna ranges of southern California continuing from north to south with the Sierra de Juárez, Sierra de San Pedro Mártir, Sierra de San Borja, Sierra de San Francisco, Sierra de la Giganta, and Sierra de la Laguna in Baja California. Palomar Mountain, home to Palomar Observatory, is in the Peninsular Ranges in San Diego County, as is Viejas Mountain and the San Ysidro Mountains. The Peninsular ranges run predominantly north-south, unlike the Transverse Ranges to their north, which mostly run east-west.


Rocks in the ranges are dominated by Mesozoic granitic rocks, derived from the same massive batholith which forms the core of the Sierra Nevada Mountains in California. They are part of a geologic province known as the Salinian Block which broke off the North American Plate as the San Andreas Fault and Gulf of California came into being.

Between this set of ranges and the Transverse Ranges is the complex Malibu Coast—Santa Monica—Hollywood fault, which exists as the border between these two mostly geologically unitary provinces.[2]

Ecology and flora


Inspiration Point Laguna Mountains
View from Inspiration Point in the Laguna Mountains, 2013. Chaparral in the foreground, Anza Borrego Desert State Park on the right of the background.

Most of the Peninsular Ranges are in the Nearctic ecozone. Several terrestrial ecoregions cover portions of the Peninsular Ranges. On western-coast side of the northern portion of the ranges the California montane chaparral and woodlands sub-ecoregion of the California chaparral and woodlands ecoregion covers in southern California and northern Baja California. On western-coast side of the southern portion of the ranges the Baja California desert ecoregion covers in the southern portion of the Peninsular Ranges in Baja California and Baja California Sur. On eastern side of northern ranges, the Sonoran Desert ecoregion covers southeastern California and northeastern Baja California as far south as the town of Loreto, Baja California Sur. On the eastern side of the Laguna Mountains in San Diego County the Anza-Borrego Desert State Park is known for its springtime profusion of Colorado Desert (Sonoran) wildflowers. On eastern-Gulf of California side of the southern portion of the ranges the Gulf of California xeric scrub ecoregion covers the range in Baja California Sur.

The higher portions of the Peninsular Ranges, especially the west-facing slopes, are home to coniferous and mixed evergreen forests. Cleveland National Forest covers much of the higher Southern California Peninsular Ranges. The vegetation includes oak woodlands and forests of Jeffrey Pine (Pinus jeffreyi) and Coulter Pine (Pinus coulteri). The Sierra Juarez and San Pedro Martir pine-oak forests cover upper slopes of Sierra Juarez and San Pedro Martir ranges in Baja California. These isolated forests, predominantly Tamarack Pine (Pinus contorta subsp. murrayana), Sugar Pine (Pinus lambertiana), Parry Pinyon (Pinus quadrifolia), White Fir (Abies concolor), California Incense Cedar (Calocedrus decurrens), and junipers. Oak species include Coast Live Oak (Quercus agrifolia), Engelmann Oak (Quercus engelmannii), Canyon Live Oak (Quercus chrysolepis), and Baja Oak (Quercus peninsularis). These higher portions of the Peninsular Ranges harbor many rare and endemic species.


Southern Baja California Sur is part of the Neotropic ecozone. The southern end of the Baja California Peninsula, including the Sierra de la Laguna Peninsular Range, was formerly an island, and evolved in relative isolation from the northern part of the peninsula and ranges. Its flora and fauna share many affinities with southern Mexico and Central America. It includes three distinct ecoregions, the Sierra de la Laguna dry forests, Sierra de la Laguna pine-oak forests, and San Lucan xeric scrub.

See also


  1. ^ Benke, Arthur C.; Cushing, Colbert E. (2005). Rivers of North America. Academic Press. p. 543. ISBN 0-12-088253-1.
  2. ^ Meigs, Andrew J.; Oskin, Michael E. (2002). "Convergence, block rotation, and structural interference across the Peninsular-Transverse Ranges boundary, eastern Santa Monica Mountains, California". In Barth, Andrew (ed.). Contributions to Crustal Evolution of the Southwestern United States. Geological Society of America. pp. 281–87. ISBN 978-0-8137-2365-5.

External links

Coordinates: 29°57′N 114°43′W / 29.95°N 114.72°W

Allium praecox

Allium praecox is a species of wild onion known by the common name early onion.

Arctostaphylos glauca

Arctostaphylos glauca is a species of manzanita known by the common name bigberry manzanita. It is native to California and Baja California, where it grows in the chaparral and woodland of coastal and inland hills.

Arctostaphylos parryana

Arctostaphylos parryana, with the common name Parry manzanita, is a species of manzanita.

Arctostaphylos rainbowensis

Arctostaphylos rainbowensis is a species of manzanita known by the common name Rainbow manzanita. It is endemic to California, where it is known only from northern San Diego and southern Riverside Counties in the Peninsular Ranges.It was named for the community of Rainbow, California, near where it is most common in the chaparral of the lower elevation coastal Santa Ana Mountains, and the only manzanita species throughout most of its range.

California mixed evergreen forest

California mixed evergreen forest is an ecoregion of the Temperate broadleaf and mixed forests biome. It is found in the mountain ranges of California and into southwestern Oregon.

The Mixed evergreen forest ecoregion is native to the Northern and Southern California Coast Ranges and Sierra Nevada of central and northern California; the Transverse Ranges and Peninsular Ranges of southern California; and the southwestern Oregon Coast Ranges.

California mixed evergreen forests occur in ecoregions of the California Floristic Province, including in areas of the California chaparral and woodlands and its sub-ecoregions, Klamath-Siskiyou Mountains forests, Northern California coastal forests, and Sierra Nevada lower montane forest. The forests of each ecoregion have a somewhat different plant community composition.

California montane chaparral and woodlands

The California montane chaparral and woodlands is an ecoregion defined by the World Wildlife Fund, spanning 7,900 square miles (20,000 km2) of mountains in the Transverse Ranges, Peninsular Ranges, and Coast Ranges of southern and central California. The ecoregion is part of the larger California chaparral and woodlands ecoregion, and belongs to the Mediterranean forests, woodlands, and scrub biome.


Chaparral () is a shrubland or heathland plant community found primarily in the US state of California and in the northern portion of the Baja California Peninsula, Mexico. It is shaped by a Mediterranean climate (mild, wet winters and hot dry summers) and wildfire, featuring summer-drought-tolerant plants with hard sclerophyllous evergreen leaves, as contrasted with the associated soft-leaved, drought-deciduous, scrub community of coastal sage scrub, found below the chaparral biome. Chaparral covers 5% of the state of California and associated Mediterranean shrubland an additional 3.5%. The name comes from the Spanish word chaparro, for evergreen oak shrubland.

Chino Hills

The Chino Hills are a mountain range on the border of Orange, Los Angeles, and San Bernardino counties, California, with a small portion in Riverside County. The Chino Hills State Park preserves open space and habitat in them.

Comarostaphylis diversifolia

Comarostaphylis diversifolia, known by the common names summer holly and California comarostaphylos, is a species of shrub in the heath family.It is native to Southern California and northern Baja California, where it grows in coastal chaparral habitat.

Cupressus revealiana

Cupressus revealiana is a rare Mexican species of conifer in the cypress family, is endemic to a small area of the State of Baja California in northwestern Mexico.The type locality is the Rincón de Santa Catarina, in the Sierra de Juárez of the Peninsular Ranges System.

Cuyamaca Mountains

The Cuyamaca Mountains, locally the Cuyamacas, are a mountain range of the Peninsular Ranges System, in San Diego County, southern California. The mountain range runs roughly northwest to southeast. The Laguna Mountains are directly adjacent to the east, with Palomar Mountain and Hot Springs Mountain more distant to the north.

Most of the range consists of extensive oak forest and chaparral, part of the California montane chaparral and woodlands ecoregion, interspersed with pine forests and lush riparian zones, featuring year round creeks and waterfalls. The San Diego River and Sweetwater River both have their headwaters in these mountains, which flow over 50 miles to the ocean. The pine forests were extensively burned by the 2003 Cedar Fire, along with many large areas of chaparral and oak woodland, which has since experienced slow and steady regrowth.

The high elevation results in snowfall throughout the winter months. Cuyamaca Peak, at 6,512 feet, is San Diego County's second highest, after Hot Springs Peak.

Elsinore Fault Zone

The Elsinore Fault Zone is a large right-lateral strike-slip geological fault structure in Southern California. The fault is part of the trilateral split of the San Andreas fault system and is one of the largest, though quietest faults in Southern California.

Laguna Mountains

The Laguna Mountains are a mountain range of the Peninsular Ranges System in eastern San Diego County, southern California. The mountains run in a northwest/southeast alignment for approximately 35 miles (56 km).

The mountains have long been inhabited by the indigenous Kumeyaay people.

Los Angeles Basin

The Los Angeles Basin is a sedimentary basin located in southern California, in a region known as the Peninsular Ranges. The basin is also connected to an anomalous group of east-west trending chains of mountains collectively known as the California Transverse Ranges. The present basin is a coastal lowland area, whose floor is marked by elongate low ridges and groups of hills that is located on the edge of the Pacific plate. The Los Angeles Basin, along with the Santa Barbara Channel, the Ventura Basin, the San Fernando Valley, and the San Gabriel Basin, lies within the greater southern California region. On the north, northeast, and east, the lowland basin is bound by the Santa Monica Mountains and Puente, Elysian, Repetto hills. To the southeast, the basin is bordered by the Santa Ana mountains and the San Joaquin Hills. The western boundary of the basin is marked by the Continental Borderland and is part of the onshore portion. The California borderland is characterized by north-west trending offshore ridges and basins. The Los Angeles Basin is notable for its great structural relief and complexity in relation to its geologic youth and small size for its prolific oil production. Yerkes et al. identify 5 major stages of the basin's evolution that begins in the Upper Cretaceous and ends in the Pleistocene. This basin can be classified as an irregular pull-apart basin accompanied by rotational tectonics during the post-early Miocene.

Peninsular myotis

The peninsular myotis (Myotis peninsularis) is a species of vesper bat. It is endemic to northwestern Mexico, found only within Baja California Sur state on the southern Baja California Peninsula. Its habitats include the southern Peninsular Ranges and deserts.

San Jacinto Mountains

The San Jacinto Mountains (Avii Hanupach in Mojave) are a mountain range in Riverside County, located east of Los Angeles in southern California in the United States. The mountains are named for one of the first Black Friars, Saint Hyacinth (San Jacinto in Spanish), who is popular patron in Latin America.

Santa Ana Mountains

The Santa Ana Mountains are a short peninsular mountain range along the coast of Southern California in the United States. They extend for approximately 61 miles (98 km) southeast of the Los Angeles Basin largely along the border between Orange and Riverside counties.

Santa Rosa Mountains (California)

The Santa Rosa Mountains are a short mountain range in the Peninsular Ranges system, located east of the Los Angeles Basin and northeast of the San Diego metropolitan area of southern California, in the southwestern United States.

Sierra de San Pedro Mártir

Sierra de San Pedro Mártir (Kiliwa: ʔxaal haq, English: mountains of Saint Peter the Martyr) is a mountain range located within southern Ensenada Municipality and southern Baja California state, of northwestern Mexico.

It is a major mountain range in the long Peninsular Ranges System, that extends from Southern California down the Baja California Peninsula into Baja California Sur state.

Statewide Faults
Southern California
Northern California
Sierra Nevada

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