Southwestern United States facts for kids
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Southwestern United States
|American Southwest, the Southwest|
Though regional definitions vary from source to source, Arizona and New Mexico (in dark red) are almost always considered the core, modern-day Southwest. The brighter red and striped states may or may not be considered part of this region. The brighter red states (California, Colorado, Nevada, and Utah) are also classified as part of the West by the U.S. Census Bureau, though the striped states are not (Oklahoma and Texas).
Others, depending on boundaries used:
Oklahoma (mainly western)
Texas (mainly western)
The Southwestern United States, also known as the American Southwest, Desert Southwest, or simply The Southwest, is the informal name for a region of the western United States. Definitions of the region's boundaries vary a great deal and have never been standardized, though many boundaries have been proposed. For example, one definition includes the stretch from the Mojave Desert in California (117° west longitude) to Carlsbad, New Mexico (104° west longitude), and from the Mexico–United States border to the southern areas of Colorado, Utah, and Nevada (39° north latitude). The largest metropolitan areas are centered around Phoenix (with an estimated population of more than 4.7 million as of 2017[update]), Las Vegas (more than 2.2 million), Tucson (more than 1 million), Albuquerque (more than 900,000), and El Paso (more than 840,000). Those five metropolitan areas have an estimated total population of more than 9.6 million as of 2017[update], with nearly 60 percent of them living in the two Arizona cities—Phoenix and Tucson.
Most of the area was part of the Viceroyalty of New Spain in the Spanish Empire before becoming part of Mexico. European settlement was almost non-existent outside New Mexico in 1848, when it became part of the United States through the Treaty of Guadalupe Hidalgo, while southern areas of Arizona and southwestern New Mexico were added in the later Gadsden Purchase.
The geography of the region is mainly made up by four features: the Mojave, Sonoran, and Chihuahuan Deserts, and the Colorado Plateau; although there are other geographical features as well, such as a portion of the Great Basin Desert. The deserts dominate the southern and western reaches of the area, while the plateau (which is largely made up of high desert) is the main feature north of the Mogollon Rim. The two major rivers of the region are the Colorado River, running in the northern and western areas, and the Rio Grande, running in the east, north to south.
Formed approximately 8000 years ago, the Chihuahuan Desert is a relatively dry desert, although it is slightly wetter than the Sonoran Desert to the west. The Chihuahuan Desert spreads across the southeastern portion of the region, covering from southeastern Arizona, across southern New Mexico, and the portion of Texas included in the Southwest. While it is the second largest desert in the United States, only a third of the desert is within the United States, with the rest in Mexico. El Paso is the major city in this desert, with other smaller cities being Las Cruces and Roswell in New Mexico.
The elevation in the Chihuahuan varies from 1970 to 5500 feet, as there are several smaller mountain ranges contained in the area, namely the San Andres and Doña Anas in New Mexico, and the Franklin Mountains, which span Texas and New Mexico in the Southwest region. The Chihuahuan is a "rain shadow" desert, formed between two mountain ranges (the Sierra Madre Occidental on the west and the Sierra Madre Oriental on the east) which block oceanic precipitation from reaching the area. The Chihuahuan Desert is considered the "most biologically diverse desert in the Western Hemisphere and one of the most diverse in the world", and includes more species of cacti than any other desert in the world. The most prolific plants in this region are agave, yucca and creosote bushes, in addition to the ubiquitous presence of various cacti species.
When people think of the desert southwest, the landscape of the Sonoran Desert is what mostly comes to mind. The Sonoran Desert makes up the southwestern portion of the Southwest; most of the desert lies in Mexico, but its United States component lies on the southeastern border of California, and the western 2/3 of southern Arizona. Rainfall averages between 4–12 inches per year, and the desert's most widely known inhabitant is the saguaro cactus, which is unique to the desert. It is bounded on the northwest by the Mojave Desert, to the north by the Colorado Plateau and to the east by the Arizona Mountains forests and the Chihuahuan Desert. Aside from the trademark saguaro, the desert has the most diverse plant life of any desert in the world, and includes many other species of cacti, including the organ-pipe, senita, prickly pear, barrel, fishhook, hedgehog, cholla, silver dollar, and jojoba. The portion of the Sonora Desert which lies in the Southwestern United States is the most populated area within the region. Six of the top ten major population centers of the region are found within its borders: Phoenix, Tucson, Mesa, Chandler, Glendale, and Scottsdale, all in Arizona. Also within its borders are Yuma and Prescott Arizona.
The most northwest portion of the American Southwest is covered by the Mojave Desert. Bordered on the south by the Sonoran Desert and the east by the Colorado Plateau, its range within the region makes up the southeast tip of Nevada, and the northwestern corner of Arizona. In terms of topography, the Mojave is very similar to the Great Basin Desert, which lies just to its north. Within the region, Las Vegas is the most populous city; other significant areas of human habitation include Laughlin and Pahrump in Nevada, and Lake Havasu City, Kingman, and Bullhead City in Arizona. The Mojave is the smallest, driest and hottest desert within the United States. The Mojave gets less than six inches of rain annually, and its elevation ranges from 3000 to 6000 feet above sea level. The most prolific vegetation is the tall Joshua tree, which grow as tall as 40 feet, and are thought to live almost 1000 years. Other major vegetation includes the Parry saltbush and the Mojave sage, both only found in the Mojave, as well as the creosote bush.
The Colorado Plateau varies from the large stands of forests in the west, including the largest stand of ponderosa pine trees in the world, to the Mesas to the east. Although not called a desert, the Colorado Plateau is mostly made up of high desert. Within the Southwest U.S. region, the Colorado is bordered to the south by the Mogollon Rim and the Sonoran Desert, to the west by the Mojave Desert, and to the east by the Rocky Mountains and the Llano Estacado. The Plateau is characterized by a series of plateaus and mesas, interspersed with canyons. The most dramatic example is the Grand Canyon. But that is one of many dramatic vistas included within the Plateau, which includes spectacular lava formations, "painted" deserts, sand dunes, and badlands. One of the most distinctive features of the Plateau is its longevity, having come into existence at least 500 million years ago. The Plateau can be divided into six sections, three of which fall into the Southwest region. Beginning with the Navajo section forming the northern boundary of the Southwestern United States, which has shallower canyons than those in the Canyonlands section just to its north; the Navajo section is bordered to the south by the Grand Canyon section, which of course is dominated by the Grand Canyon; and the southeastern-most portion of the Plateau is the Datil section, consisting of valleys, mesas, and volcanic formations. Albuquerque is the most populous city within the portion contained in the Southwest region, but Sante Fe, New Mexico and Flagstaff, Arizona, are also significant population centers.
Geographer D. W. Meinig defines the Southwest in a very similar fashion to Reed: the portion of New Mexico west of the Llano Estacado and the portion of Arizona east of the Mojave-Sonoran Desert and south of the "canyon lands" and also including the El Paso district of western Texas and the southernmost part of Colorado. Meinig breaks the Southwest down into four distinct subregions. He calls the first subregion "Northern New Mexico", and describes it as focused on Albuquerque and Santa Fe. It extends from the San Luis Valley of southern Colorado to south of Socorro and including the Manzano Mountains, with an east-west breadth in the north stretching from the upper Canadian River to the upper San Juan River. The area around Albuquerque is sometimes called Central New Mexico.
"Central Arizona" is a vast metropolitan area spread across one contiguous sprawling oasis, essentially equivalent to the Phoenix metropolitan area. The city of Phoenix is the largest urban center, and located in the approximate center of the area that includes Tempe, Mesa, and many others.
Meinig calls the third subregion "El Paso, Tucson, and the Southern Borderlands". While El Paso and Tucson are distinctly different cities, they serve as anchor points to the hinterland between them. Tucson occupies a large oasis at the western end of the El Paso-Tucson corridor. The region between the two cities is a major transportation trunk with settlements servicing both highway and railway needs. There are also large mining operations, ranches, and agricultural oases. Both El Paso and Tucson have large military installations nearby; Fort Bliss and White Sands Missile Range north of El Paso in New Mexico, and, near Tucson, the Davis-Monthan Air Force Base. About 70 miles (110 km) to the southeast are the research facilities at Fort Huachuca. These military installations form a kind of hinterland around the El Paso-Tucson region, and are served by scientific and residential communities such as Sierra Vista, Las Cruces, and Alamogordo. El Paso's influence extends north into the Mesilla Valley, and southeast along the Rio Grande into the Trans-Pecos region of Texas.
The fourth subregion Meinig calls the "Northern Corridor and Navajolands". A major highway and railway trunk which connects Albuquerque and Flagstaff. Just north of the transportation trunk are large blocks of American Indian land.
Vegetation and terrain
Vegetation of the southwest generally includes various types of yucca, along with saguaro cactus, barrel cactus, prickly pear cactus, desert spoon, creosote bush, sagebrush, and greasewood. Although cacti is thought to only grow in Arizona and New Mexico, many native cacti grow throughout Nevada, Utah, Colorado, and west Texas. Steppe is also located all over the high plains areas in Colorado, New Mexico, and Texas. The mountains of the southwestern states have large tracts of alpine trees.
Landscape features of the core southwestern areas include mountains, canyons, mesas, buttes, high broad basins, plateaus, desert lands, and some plains, characteristic of the Basin and Range Province. The entire southwestern region features semi-arid to arid terrain. The far eastern part of southwestern Texas, for example the Texas Hill Country, consists of dry, tall, and rugged rocky hills of limestone and granite. South Texas and the Rio Grande Valley is mostly flat with many places consisting of scrub and bare topsoil, much like the deserts further west.
The region has an extremely diverse bird population, with hundreds of species being found in the American Southwest. In the Chiricahua Mountains alone, in southeastern Arizona, there can be found more than 400 species. Species include Canadian (Branta canadensis) and snow geese, sandhill cranes (Grus canadensis), and the roadrunner, the state bird of New Mexico and most famous bird in the region, is found in all states of the Southwest. Birds of prey include the red-tailed hawk (Buteo jamaicensis), Cooper's hawk (Accipiter cooperii), the osprey (Pandion haliaetus), golden eagles (Aquila chrysaetos), Harris's hawk (Parabuteo unicinctus), American kestrel (Falco sparverius), peregrine falcon (Falco peregrinus), the gray hawk (Buteo plagiatus), the barn owl (Tyto alba), the western screech owl (Megascops kennicottii), the great horned owl (Bubo virginianus), the elf owl (Micrathene whitneyi), and the burrowing owl (Athene cunicularia)
Other bird species include the turkey vulture (Cathartes aura), the black vulture (Coragyps atratus), the northern cardinal (Cardinalis cardinalis), the blue grosbeak (Passerina caerulea), the house finch (Haemorhous mexicanus), the lesser goldfinch (Spinus psaltria), the broad-billed hummingbird (Cynanthus latirostris), the black-chinned hummingbird (Archilochus alexandri), Costa's hummingbird (Calypte costae), Gambel's quail (Callipepla gambelii), the common raven (Corvus corax), the Gila woodpecker (Melanerpes uropygialis), the gilded flicker (Colaptes chrysoides), the cactus wren (Campylorhynchus brunneicapillus), and the rock wren (Salpinctes obsoletus). Four types of doves call the Southwest home: the white-winged dove (Zenaida asiatica), the mourning dove (Zenaida macroura), the common ground dove (Columbina passerina), and the Inca dove (Columbina inca).
Mammal species include the bobcat, coyote, black bear, black-tailed jackrabbit, desert cottontail, desert bighorn sheep, mule deer, white-tailed deer, gray fox, mountain lion, river otter, long-tailed weasel, western spotted skunk, pronghorn, raccoon, and Ord's kangaroo rat, all of which can be found in parts of every southwestern state. Elk are found in parts of Colorado, New Mexico, Utah, and Arizona. White-nosed coati, coati, and collared peccary—or javelina—in the Southwest are normally found in southern areas of Arizona, New Mexico, and Texas near the Mexican border. Jaguars can be found in the bootheel region of Southwestern New Mexico. The Mexican wolf (Canis lupus baileyi) was reintroduced to Arizona and New Mexico in 1998. A U.S. Fish and Wildlife Service study reported a minimum population of 109 Mexican wolves in southwest New Mexico and southeast Arizona at the end of 2014.
There is a large contingent of snakes native to the region. Among them include: the rosy boa (Lichanura trivirgata); several sub-species of the glossy snake (Arizona elegans); the Trans-Pecos ratsnake (Bogertophis subocularis); several sub-species of shovel-nosed snakes; several sub-species of kingsnake, including the desert kingsnake (Lampropeltis getula splendida) and the Arizona mountain kingsnake (Lampropeltis pyromelana); the Arizona coral snake (Micruroides euryxanthus); the western diamondback rattlesnake (Crotalus atrox); the Trans-Pecos copperhead (Agkistrodon contortrix pictigaster); the Sonoran sidewinder (Crotalus cerastes cercobombus); the Arizona black rattlesnake (Crotalus oreganus cerberus); the western rattlesnake (Crotalus viridis); the Grand Canyon rattlesnake (Crotalus oreganus abyssus), found only in Arizona; several sub-species of the ridge-nosed rattlesnake (Crotalus willardi), the most recent rattlesnake species to be discovered in the United States, including the New Mexico ridge-nosed rattlesnake (Crotalus willardi obscurus), and the Arizona ridge-nosed rattlesnake, the state reptile of Arizona; and the desert massasauga (Sistrurus catenatus edwardsii).
Other reptiles in the region include lizards and turtles. Lizards are highly represented in the region, the most distinctive denizen being the Gila monster, native only to the American Southwest and the state of Sonora in Mexico. Other lizards include: Sonoran collared lizard (Crotaphytus nebrius); several types of geckos, including western banded gecko (Coleonyx variegatus), the common house gecko (Hemidactylus frenatus), and the Mediterranean house gecko (Hemidactylus turcicus), the last two species being non-native to the region but have been introduced; the desert iguana (Dipsosaurus dorsalis); the chuckwalla (Sauromalus ater); the greater earless lizard (Cophosaurus texanus scitulus); several sub-species of horned lizards (Phrynosoma); numerous species of spiny lizards (Sceloporus); Gilbert's skink (Plestiodon gilberti); the western skink (Plestiodon skiltonianus); Trans-Pecos striped whiptail (Aspidoscelis inornata heptagrammus); and the Arizona night lizard (Xantusia arizonae). Turtles are less numerous than their other reptilian counterparts, but several are found in the region, including: the western painted turtle (Chrysemys picta bellii); the Rio Grande cooter (Pseudemys gorzugi); the desert box turtle (Terrapene ornata luteola); the Big Bend slider (Trachemys gaigeae gaigeae); the Sonora mud turtle (Kinosternon sonoriense); and the desert tortoise (Gopherus agassizii).
Amphibians include numerous toads and frogs in the American Southwest. Toads which can be found in the region include: the Great Plains toad (Anaxyrus cognatus); the green toad (Anaxyrus debilis); the Arizona toad (Anaxyrus microscaphus); the New Mexico spadefoot (Spea multiplicata stagnalis); and the Colorado River toad (Incilius alvarius), also known as the Sonoran Desert toad. Frog representation includes: western barking frog (Craugastor augusti); the canyon tree frog (Hyla arenicolor); the Arizona treefrog (Hyla wrightorum); the western chorus frog (Pseudacris triseriata); Chiricahua leopard frog (Lithobates chiricahuensis); and the relict leopard frog (Lithobates onca). There are quite a few salamanders throughout the region, including: the Arizona tiger salamander (Ambystoma mavortium nebulosum) and the painted ensatina (Ensatina eschscholtzii picta).
The southwestern United States features a semi-arid to arid climate, depending on the location. Much of the Southwest is an arid desert climate, but higher elevations in the mountains in each state, with the exception of West Texas, feature alpine climates with very large amounts of snow. The metropolitan areas of Phoenix, Tucson, Las Vegas, and El Paso hardly ever receive any snow at all, as they are strictly desert lands with mountains. Albuquerque receives less snow than other cities, but still receives significant snowfalls occasionally in the winter time. Although it snows in this region, the snow in this part of the United States melts rapidly, often before nightfall. This is due mainly to the higher altitude and abundant sunshine in these states.
Nevada and Arizona are both generally arid with desert lands and mountains, and receive large amounts of snow in the higher elevations in and near the mountains. New Mexico, Utah, and Colorado are generally arid, with desert lands and mountains as well. They all receive decent amounts of snow and large amounts of snow in the high elevations in the mountains, although some areas in far southwestern and southern New Mexico do not receive much snow at all at lower elevations. West Texas is generally arid as well but does not receive the same amount of snow that the other southwestern states receive at their high elevations. The terrain of western Texas in the Southwest is the flat, rolling land of the plains, which eventually turns into a desert with some hills. There are significant mountains as well in west Texas upon reaching the Trans-Pecos area.
The term "High Desert" is also synonymous with this region. The High Desert is generally defined as the Mojave Desert, which extends from inland southern California into southern Nevada, and southwestern Utah. The High Desert also extends into other parts of the Northwest, such as the Red Desert in southwestern Wyoming. The High Desert is very different from the general desert lands found in Arizona, in the Sonoran Desert. This area of the desert land generally sits at a very high elevation, much higher than the normal desert land, and can receive very cold temperatures at night in the winter (with the exception of California, southern Nevada and southwestern Utah), sometimes near zero degrees on very cold nights. The High Desert also receives a decent amount of snowfall in the winter (with the exception of California, southern Nevada and southwestern Utah) but melts very quickly.
Other areas of the Southwest may also be referred to as the "High Desert" such as the Colorado Plateau. The desert lands found in Eastern Utah, Northern Arizona, Colorado and New Mexico are usually referred to as the high desert. Colorado has scattered desert lands found in southern, southwestern, western, and the northwestern parts of the state. These scattered desert lands are located in and around areas such as, the Roan Plateau, Dinosaur National Monument, Colorado National Monument, Royal Gorge, Cortez, Dove Creek, Canyons of the Ancients National Monument, Four Corners Monument, Montrose, Blue Mesa Reservoir, Pueblo, San Luis Valley, Great Sand Dunes and Joshua Tree National Park. Besides the Chihuahuan Desert, lands in southwestern and southern New Mexico, they also have scattered desert lands in the northwestern and northern portions of their state, which is referred to as the high desert.
During El Niño, winters and springs are generally colder and wetter across southern portions of the region, while the northern portion stays warmer and drier due to a southern jet stream. Under La Niña, the opposite happens, meaning the cool and wet weather tends to stay further north.
National parks, monuments and forests
The southwestern United States contains many well-known national parks including Grand Canyon in Arizona, Death Valley in California, Great Sand Dunes in Colorado, Arches in Utah, Big Bend in Texas, Great Basin in Nevada, and White Sands in New Mexico.
Arizona parks and monuments include Grand Canyon, Monument Valley (a Navajo Nation park), Petrified Forest, and Saguaro national parks; the national monuments of Agua Fria, Canyon de Chelly, Casa Grande Ruins, Chiricahua, Ironwood Forest, Montezuma Castle, Navajo, Organ Pipe Cactus, Pipe Spring, Sonoran Desert, Sunset Crater, Tonto, Tuzigoot, Vermilion Cliffs, Walnut Canyon, and Wupatki. Other federal areas include the Apache–Sitgreaves National Forests and Tumacacori National Historical Park.
Southern California parks and monuments include Death Valley and Joshua Tree national parks; the national monuments of Castle Mountains, Mojave Trails, Sand to Snow, and San Gabriel Mountains; and Mojave National Preserve.
Colorado parks and monuments include Great Sand Dunes, Black Canyon of the Gunnison, and Mesa Verde national parks; the national monuments of Browns Canyon, Canyons of the Ancients, Colorado, Hovenweep, and Yucca House. Other federal areas include Curecanti National Recreation Area and Bent's Old Fort National Historic Site; as well as the national forests of San Isabel, San Juan, and Uncompahgre.
Nevada has one national park at Great Basin, and the national monuments of Basin and Range, Gold Butte, and Tule Springs Fossil Beds. Other federal areas include Humboldt-Toiyabe National Forest, Lake Mead National Recreation Area, and Red Rock Canyon National Conservation Area.
New Mexico has two national parks, at Carlsbad Caverns and White Sands. National monuments include Aztec Ruins, Bandelier, El Malpais, El Morro, Gila Cliff Dwellings, Kasha-Katuwe Tent Rocks, Organ Mountains–Desert Peaks, Petroglyph, Rio Grande del Norte, and Salinas Pueblo Missions. Other federal park areas include Chaco Culture National Historical Park, Pecos National Historical Park, Sevilleta National Wildlife Refuge, and the national forests of Apache, Carson, Gila, Lincoln, and Santa Fe.
Utah national parks include Arches, Bryce Canyon, Canyonlands, Capitol Reef, and Zion. National monuments include Bears Ears, Cedar Breaks, Grand Staircase-Escalante, Hovenweep (also in Colorado), Natural Bridges, and Rainbow Bridge. Other federal areas include Glen Canyon National Recreation Area, Dixie National Forest, and Manti–La Sal National Forest.
Hispanic Americans (mostly Mexican Americans, with large populations of Spanish Americans) can be found in large numbers in every major city in the Southwest such as El Paso (80%), San Antonio (63%), Albuquerque (47%), Phoenix (43%), Tucson (41%), Las Vegas (32%), and Mesa (27%).
Very large Hispanic American populations can also be found in the smaller cities such as Eagle Pass (96%), Las Cruces (56%), Yuma (55%), Blythe (53%), Pueblo (48%), Santa Fe (48%), and Glendale (36%). Many small towns throughout the southwestern states also have significantly large Latino populations.
The largest African American populations in the Southwest can be found in Las Vegas (10%), San Antonio (7%), and Phoenix (5%).
The largest Asian American populations in the southwest can be found in Nevada and Utah, with some significant Asian population in Phoenix. The most significant American Indian populations can be found in New Mexico and Arizona.
Cities and urban areas
The area also contains many of the nation's largest cities and metropolitan areas, despite relatively low population density in rural areas. Phoenix is the fifth most populous city in the country, and Albuquerque and Las Vegas were some of the fastest-growing cities in the United States. Also, the region as a whole has witnessed some of the highest population growth in the United States, and according to the US Census Bureau, in 2008–2009, Utah was the fastest-growing state in America. As of the 2010 Census, Nevada was the fastest-growing state in the United States, with an increase of 35.1% in the last ten years. Additionally, Arizona (24.6%), Utah (23.8%), Texas (20.6%), and Colorado (16.9%) were all in the top ten fastest-growing states as well.
The largest metropolitan areas are centered around Phoenix (with an estimated population of more than 4.7 million as of 2017[update]), Las Vegas (more than 2.2 million), Tucson (more than 1 million), Albuquerque (more than 900,000), and El Paso (more than 840,000). Those five metropolitan areas have an estimated total population of more than 9.6 million as of 2017[update], with nearly 60 percent of them living in the two Arizona cities—Phoenix and Tucson.
2. El Paso (5th largest MSA)
3. Las Vegas (2nd largest MSA)
4. Albuquerque (also the 4th largest MSA)
5. Tucson (3rd largest MSA)
Largest cities and metropolitan areas (2010 census)
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