The Peninsular Ranges (also called the Lower California province) are a group of mountain ranges that stretch from

Southern California Southern California (commonly shortened to SoCal) is a geographic and Cultural area, cultural List of regions of California, region that generally comprises the southern portion of the U.S. state of California. Its densely populated coastal reg ...

to the southern tip of the Baja California peninsula; they are part of the North American

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. Althoug ...

, which run along the

Pacific coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas North America Countries on the western side of North America have a Pacific coast as their western or south-western border. One of th ...

from Alaska to Mexico. Elevations range from .

Geography

The Peninsular Ranges include the

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 southeast of the Los Angeles Basin largely along the border between Orange and Riversid ...

, the

Temescal Mountains The Temescal Mountains, also known as the Sierra Temescal ( Spanish for "sweat lodge range"), are one of the northernmost mountain ranges of the Peninsular Ranges in western Riverside County, in Southern California in the United States. They ex ...

, other mountains and ranges of the

Perris Block The Perris Block is the central block of three major fault-bounded blocks of the northern part of the Peninsular Ranges. The Perris Block lies between the Santa Ana Block to the west and the San Jacinto Block to the east. The Perris Block, was n ...

, the

San Jacinto Mountains The San Jacinto Mountains ()Munro, P., et al. ''A Mojave Dictionary''. Los Angeles: UCLA. 1992. are a mountain range in Riverside County, California, Riverside County, located east of Los Angeles, California, Los Angeles in southern California i ...

, the

Laguna Mountains The Laguna Mountains are a mountain range of the Peninsular Ranges in eastern San Diego County, California. The mountains run in a northwest/southeast alignment for approximately . The mountains have long been inhabited by the indigenous Kumey ...

of southern California continuing from north to south with the

Sierra de Juárez The Sierra de Juárez, also known as the Sierra Juarez, is a mountain range located in Tecate Municipality and northern Ensenada Municipality, within the northern Baja California state of northwestern Mexico. It is a major mountain range in ...

, the

Sierra de San Pedro Mártir Sierra de San Pedro Mártir ( Kiliwa: ʔxaal haq, ) 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, ...

, the Sierra de San Borja, the

Sierra de San Francisco The Sierra de San Francisco is a mountain range in Mulegé Municipality of the northern region of Baja California Sur state, in northwestern Mexico. Geography The Sierra de San Francisco are on the eastern side of the Baja California Peninsula, n ...

, the

Sierra de la Giganta The Sierra de la Giganta is a mountain range of eastern Baja California Sur state, located on the southern Baja California Peninsula in northwestern Mexico. It is a mountain range of the Peninsular Ranges System, which extends from Southern Cal ...

, and the

Sierra de la Laguna The Sierra de la Laguna is a mountain range at the southern end of the Baja California peninsula in Mexico, and is the southernmost range of the Peninsular Ranges System. It is located in La Paz Municipality, Baja California Sur, La Paz Municipa ...

in Baja California.

Palomar Mountain Palomar Mountain ( ; ) is a mountain ridge in the Peninsular Ranges in northern San Diego County, California. It is known as the location of Palomar Observatory and Hale Telescope, and known for Palomar Mountain State Park. History The Luise� ...

, home to

Palomar Observatory The Palomar Observatory is an astronomical research observatory in the Palomar Mountains of San Diego County, California, United States. It is owned and operated by the California Institute of Technology (Caltech). Research time at the observat ...

, is in the Peninsular Ranges in

San Diego County San Diego County (), officially the County of San Diego, is a county in the southwest corner of the U.S. state of California, north to its border with Mexico. As of the 2020 census, the population was 3,298,634; it is the second-most populous ...

, as are the

San Ysidro Mountains The San Ysidro Mountains are a mountain range in southern San Diego County, California, and Baja California, Mexico. The mountains are a rugged coastal foothill range of the Peninsular Ranges system. Major peaks include the highest summit of the ...

and

Viejas Mountain Viejas Mountain is a mountain in San Diego County, California. At , Viejas Mountain is the 48th tallest peak in San Diego County. The mountain can be seen from parts of metropolitan San Diego. The summit is about northeast of the community of ...

. The Peninsular Ranges run predominantly north-south, unlike the

Transverse Ranges The Transverse Ranges are a group of mountain ranges of Southern California, in the Pacific Coast Ranges physiographic region in North America. The Transverse Ranges begin at the southern end of the California Coast Ranges and lie within Santa Ba ...

to their north, which mostly run east-west.

Geology

Rocks in the ranges are dominated by

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

granitic rocks A granitoid is a broad term referring to a diverse group of coarse-grained igneous rocks that are widely distributed across the globe, covering a significant portion of the Earth's exposed surface and constituting a large part of the continental ...

, derived from the same massive batholith which forms the core of the

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

Mountains in California. They are part of a geologic province known as the

Salinian Block The Salinian Block or Salinian terrane is a geologic terrane which lies west of the main trace of the San Andreas Fault system in California. It is bounded on the south by the Big Pine Fault in Ventura County and on the west by the Nacimiento Fau ...

which broke off the North American plate as the

San Andreas Fault The San Andreas Fault is a continental Fault (geology)#Strike-slip faults, right-lateral strike-slip transform fault that extends roughly through the U.S. state of California. It forms part of the tectonics, tectonic boundary between the Paci ...

and

Gulf of California The Gulf of California (), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Vermejo''), is a marginal sea of the Pacific Ocean that separates the Baja California peninsula from ...

came into being. Between the Peninsular Ranges and the

lies the complex Malibu Coast—Santa Monica— Hollywood fault, which exists as the border between these two mostly geologically unitary provinces.

Ecology and flora

Nearctic

Most of the Peninsular Ranges are in the

Nearctic realm The Nearctic realm is one of the eight biogeographic realms constituting the Earth's land surface. The Nearctic realm covers most of North America, including Greenland, Central Florida, and the highlands of Mexico. The parts of North America t ...

. Several

terrestrial ecoregions An ecoregion (ecological region) is an ecology, ecological and Geography, geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of la ...

cover portions of the Peninsular Ranges. On the western side of the northern portion of the ranges, the montane sub-ecoregion of the

California chaparral and woodlands The California chaparral and woodlands is a terrestrial ecoregion of southwestern Oregon, northern, central, and southern California (United States) and northwestern Baja California (Mexico), located on the west coast of North America. It is a ...

ecoregion covers southern California and northern Baja California. On the western side of the southern portion of the ranges, the

Baja California desert The Baja California desert () is a desert ecoregion of Mexico's Baja California peninsula. This ecoregion occupies the western portion of the Baja California peninsula, and occupies most of the Mexican states of Baja California Sur and Baja Cali ...

ecoregion covers the southern portion of the Peninsular Ranges in Baja California and

Baja California Sur Baja California Sur, officially the Free and Sovereign State of Baja California Sur, is a state in Mexico. It is the 31st and last state to be admitted, in 1974. It is also the second least populated Mexican state and the ninth-largest state by ...

. On the eastern side of the northern ranges, the

Sonoran Desert The Sonoran Desert () is a hot desert and ecoregion in North America that covers the northwestern Mexican states of Sonora, Baja California, and Baja California Sur, as well as part of the Southwestern United States (in Arizona and California). It ...

ecoregion covers southeastern California and northeastern Baja California as far south as the town of Loreto. On the eastern side of the Laguna Mountains in

Anza-Borrego Desert State Park Anza-Borrego Desert State Park (, ''Help:Pronunciation respelling key, AN-zə bə-RAY-goh'') is a California State Park located within the Colorado Desert of Southern California, United States. Created in 1932, the park takes its name from 18th ...

is known for its springtime profusion of

Colorado Desert The Colorado Desert is a part of the larger Sonoran Desert located in California, United States, and Baja California, Mexico. It encompasses approximately , including the heavily irrigated Coachella, Imperial and Mexicali valleys. It is home to ...

(Sonoran) wildflowers. On the eastern (

) 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

conifer Conifers () are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a sin ...

ous and mixed evergreen forests.

Cleveland National Forest Cleveland National Forest is a National forest (United States), U.S. national forest in Southern California that encompasses 460,000 acres/ of inland Montane ecosystems, montane regions. It is approximately 60 miles from the Pacific Ocean, withi ...

covers much of the higher

Peninsular Ranges. The vegetation includes

oak woodland An oak woodland is a plant community with a tree canopy dominated by oaks (''Quercus spp.''). In terms of canopy closure, oak woodlands are intermediate between oak savanna, which is more open, and oak forest, which is more closed. Although the c ...

s and forests of Jeffrey pine (''Pinus jeffreyi'') and Coulter pine (''Pinus coulteri''). The

Sierra Juarez and San Pedro Martir pine-oak forests Sierra (Spanish for "mountain range" or "mountain chain" and "saw", from Latin '' serra'') may refer to the following: Places Mountains and mountain ranges * Sierra de Juárez, a mountain range in Baja California, Mexico * Sierra de las Nieve ...

cover the upper slopes of the Sierra Juarez and San Pedro Martir ranges in Baja California. These isolated forests are predominantly composed of tamarack pine (''Pinus contorta'' subsp. ''murrayana''), sugar pine (''Pinus lambertiana''), Parry pinyon ''(Pinus quadrifolia)'', white fir (''Abies concolor''), California incense cedar (''Calocedrus decurrens''), and

juniper Junipers are coniferous trees and shrubs in the genus ''Juniperus'' ( ) of the cypress family Cupressaceae. Depending on the taxonomy, between 50 and 67 species of junipers are widely distributed throughout the Northern Hemisphere as far south ...

s. 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 Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

species.

Neotropic

Southern Baja California Sur is part of the

Neotropical realm The Neotropical realm is one of the eight biogeographic realms constituting Earth's land surface. Physically, it includes the tropics, tropical Ecoregion#Terrestrial, terrestrial ecoregions of the Americas and the entire South American temperat ...

. The southern end of the Baja California Peninsula, including the

Peninsular Range, was, like the rest of the peninsula, originally part of the Mexican mainland. It was sheared off the mainland, becoming at one time 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 Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

. It includes three distinct ecoregions, the

Sierra de la Laguna dry forests The Sierra de la Laguna dry forests are a tropical and subtropical dry broadleaf forests, subtropical dry forest terrestrial ecoregion, ecoregion of the southern Baja California Peninsula in Mexico. Geography The dry forests cover the lower elev ...

Sierra de la Laguna pine-oak forests Sierra (Spanish for "mountain range" or "mountain chain" and "saw", from Latin '' serra'') may refer to the following: Places Mountains and mountain ranges * Sierra de Juárez, a mountain range in Baja California, Mexico * Sierra de las Nieve ...

, and San Lucan xeric scrub.

References

{{coord, 32.51480265, -115.67512390, format=dms, source:kolossus-dewiki, display=title Lists of mountain ranges Geologic provinces of California Mountain ranges of Baja California Mountain ranges of Baja California Sur Mountain ranges of Mexico Mountain ranges of San Diego County, California Mountain ranges of Southern California Pacific Coast Ranges Physiographic sections Physiographic regions of Mexico Physiographic regions of the United States

Geography

Geology

Ecology and flora

Nearctic

Neotropic

See also

References