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 region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most po ...

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

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 th ...

, which run along the

Pacific Coast Pacific coast may be used to reference any coastline that borders the Pacific Ocean. Geography Americas Countries on the western side of the Americas have a Pacific coast as their western or southwestern border, except for Panama, where the Pac ...

from Alaska to Mexico.

Elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § Vert ...

s 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 Riverside co ...

, Temescal and other mountains and ranges of the

Perris Block The Perris Block is the central block of three major Fault block, 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 B ...

, San Jacinto and Laguna ranges 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, en, 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 ran ...

Sierra de San Borja The Sierra de San Borja, also known as Sierra La Libertad is a mountain range on the Baja California Peninsula of Mexico. It is one of the Peninsular Ranges which form the backbone of Baja California. The Sierra de San Borja is located betwe ...

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, ...

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

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 and Los Cabos Municipality of sout ...

in Baja California.

Palomar Mountain Palomar Mountain ( ; es, Monte Palomar ) is a mountain ridge in the Peninsular Ranges in northern San Diego County. It is famous as the location of the Palomar Observatory and Hale Telescope, and known for the Palomar Mountain State Park. His ...

, home to Palomar Observatory, is in the Peninsular Ranges in

San Diego County San Diego County (), officially the County of San Diego, is a county in the southwestern corner of the U.S. state of California. As of the 2020 census, the population was 3,298,634, making it California's second-most populous county and the f ...

, as are

Viejas Mountain Viejas Mountain is a mountain in San Diego County in the U.S. state of 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 o ...

and the San Ysidro Mountains. 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 B ...

to their north, which mostly run east-west.

Geology

Rocks in the ranges are dominated by

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

granitic rock A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quartz- ...

s, 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 primarily ...

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 The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...

as the

San Andreas Fault The San Andreas Fault is a continental transform fault that extends roughly through California. It forms the tectonics, tectonic boundary between the Pacific Plate and the North American Plate, and its motion is Fault (geology)#Strike-slip fau ...

and

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

came into being. Between this set of ranges and the

is the complex Malibu Coast—Santa Monica—

Hollywood fault The Hollywood fault is an active fault of approximately in length located along the northern edge of the Los Angeles basin. It is part of a system of seismically active Fold (geology), folds and Fault (geology), faults that constitute the comple ...

, 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) 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 l ...

cover portions of the Peninsular Ranges. On western-coast side of the northern portion of the ranges the

California montane chaparral and woodlands The California montane chaparral and woodlands is an ecoregion defined by the World Wildlife Fund, spanning of mountains in the Transverse Ranges, Peninsular Ranges, and Coast Ranges of southern and central California. The ecoregion is part of ...

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 The Baja California Desert ( es, Desierto de Baja California) 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 B ...

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

Baja California Sur Baja California Sur (; 'South Lower California'), officially the Free and Sovereign State of Baja California Sur ( es, Estado Libre y Soberano de Baja California Sur), is the least populated state and the 31st admitted state of the 32 federal ent ...

. On eastern side of northern ranges, the

Sonoran Desert The Sonoran Desert ( es, Desierto de Sonora) is a desert in North America and ecoregion 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 ...

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

the

Anza-Borrego Desert State Park Anza-Borrego Desert State Park (, '' AN-zə bə-RAY-goh'') is a California State Park located within the Colorado Desert of southern California, United States. The park takes its name from 18th century Spanish explorer Juan Bautista de Anza and ...

is known for its springtime profusion of

Colorado Desert California's Colorado Desert is a part of the larger Sonoran Desert. It encompasses approximately , including the heavily irrigated Coachella and Imperial valleys. It is home to many unique flora and fauna. Geography and geology The Colorado De ...

(Sonoran) wildflowers. On eastern-

side of the southern portion of the ranges the

Gulf of California xeric scrub The Gulf of California xeric scrub ( es, Matorral xerófilo del Golfo de California) is a deserts and xeric shrublands, xeric shrubland ecoregion of Mexico's Baja California Peninsula. Geography The Gulf of California xeric scrub covers an area ...

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 single ...

ous and mixed evergreen forests.

Cleveland National Forest Cleveland National Forest encompasses 460,000 acres (), mostly of chaparral, with a few riparian areas. A warm dry mediterranean climate prevails over the forest. It is the southernmost U.S. National Forest of California. It is administered by ...

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 ...

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" 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 Nieves, a mountain range i ...

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

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, from the Arcti ...

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 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 found elsew ...

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 tropical terrestrial ecoregions of the Americas and the entire South American temperate zone. Definition In bioge ...

. 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 ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

. It includes three distinct ecoregions, the

Sierra de la Laguna dry forests The Sierra de la Laguna dry forests are a subtropical dry forest ecoregion of the southern Baja California Peninsula in Mexico. Geography The dry forests cover the lower elevations of the Sierra de la Laguna, from elevation. They are surroun ...

, Sierra de la Laguna pine-oak forests, and

San Lucan xeric scrub The San Lucan xeric scrub is a xeric shrubland ecoregion of the southernmost Baja California Peninsula, in Los Cabos Municipality and eastern La Paz Municipality of southern Baja California Sur state, Mexico. Geography The San Lucan xeric scr ...

References

External links

{{California Faults 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