The Intermontane Plateaus of the Western United States is one of eight U.S. Physiographic regions (divisions) of the physical geography of the contiguous United States. The region is composed of intermontane plateaus and mountain ranges. It is subdivided into physiographic provinces, which are each subdivided into physiographic sections.
The Mojave Desert is an arid rain-shadow desert and the driest desert in North America. It is in the Southwestern United States, primarily within southeastern California and southern Nevada, and it occupies 47,877 sq mi. Small areas also extend into Utah and Arizona. Its boundaries are generally noted by the presence of Joshua trees, which are native only to the Mojave Desert and are considered an indicator species, and it is believed to support an additional 1,750 to 2,000 species of plants. The central part of the desert is sparsely populated, while its peripheries support large communities such as Las Vegas, Barstow, Lancaster, Palmdale, Victorville, and St. George.
The Chocolate Mountains of California are located in Imperial and Riverside counties in the Colorado Desert of Southern California. The mountains stretch more than 60 miles (100 km) in a northwest to southeast direction, and are located east of the Salton Sea and south and west of the Chuckwalla Mountains and the Colorado River. To the northwest lie the Orocopia Mountains.
The Chuckwalla Mountains are a mountain range in the transition zone between the Colorado Desert—Sonoran Desert and the Mojave Desert, climatically and vegetationally, in Riverside County of southern California.
Newberry Springs is an unincorporated community in the western Mojave Desert of Southern California, located at the foot of the Newberry Mountains in San Bernardino County, California, United States. The population at the 2000 census was 2,895.
The Sheep Hole Mountains are a mountain range in the Mojave Desert, to the north of Joshua Tree National Park, in San Bernardino County, California. The mountains were once Chemehuevi hunting grounds.
The Clipper Mountains are located in the Eastern Mojave Desert and protected within Mojave Trails National Monument, in San Bernardino County, California.
The Turtle Mountains, are located in northeastern San Bernardino County, in the southeastern part of California. The colorful Turtle Mountains vary from deep reds, browns, tans and grays, to black. The area has numerous springs and seeps. The Turtle Mountains are also a National Natural Landmark, with two mountain sections of entirely different composition.
The Newberry Mountains of California are located southeast of Barstow in the Mojave Desert, in San Bernardino County, California. The Rodman Mountains lie to the southeast of the range, while the Ord Mountains lie to the southwest.
The Santa Rosa and San Jacinto Mountains National Monument is a National Monument in southern California. It includes portions of the Santa Rosa and San Jacinto mountain ranges, the northernmost ones of the Peninsular Ranges system. The national monument covers portions of Riverside County, west of the Coachella Valley, approximately 100 miles (160 km) southeast of downtown Los Angeles.
Old Woman Mountains Wilderness is a wilderness area in the Old Woman Mountains of the eastern Mojave Desert. It is located south of Essex in San Bernardino County, California.
The Kofa Mountains of Yuma and La Paz counties in Arizona is the central mountain range of the Kofa National Wildlife Refuge. The range lies about 60 miles northeast of Yuma in the southwestern part of the state. Kofa Wilderness takes up 547,719 acres of the refuge, making it the second largest wilderness area in Arizona. The equally extensive Castle Dome Mountains comprise the southern refuge border; the western end of the Tank Mountains are in the southeast of the wildlife refuge, and the New Water Wilderness in the New Water Mountains ends the extension of the Kofa National Wildlife Refuge to the north. Scenic "King Valley" is south of the Kofa Mountains between the Castle Dome Mountains.
The Eldorado Mountains, also called the El Dorado Mountains, are a north-south trending mountain range in southeast Nevada bordering west of the south-flowing Colorado River; the endorheic Eldorado Valley borders the range to the west, and the range is also on the western border of the Colorado River's Black Canyon of the Colorado, and El Dorado Canyon on the river. The range is 50 miles (80 km) southeast of Las Vegas, Nevada; and the Eldorado Mountains connect with the Highland and Newberry mountains.
The Kiavah Wilderness is a federally designated wilderness area located in the Mojave Desert, Scodie Mountains, and southern Sierra Nevada in Kern County, California, United States. California State Route 178 connects the town of Lake Isabella to State Highway 14 in the east, crossing Walker Pass at the north boundary of the wilderness.
Arrow Canyon Wilderness is a 27,530-acre (11,140 ha) wilderness area located in Clark County in the U.S. state of Nevada. It received wilderness designation with the passage of the Clark County Conservation of Public Land and Natural Resources Act of 2002 and protects the northern portion of the Arrow Canyon Range. The Arrow Canyon Wilderness is managed by the Bureau of Land Management.
The Piper Mountain Wilderness is a federally designated wilderness area located in the White Mountains 20 miles (32 km) northeast of Big Pine, California in Inyo County, California.
The Sylvania Mountains Wilderness is a federally designated wilderness area located 30 miles (48 km) east of Bishop in the state of California. The wilderness is 18,677acres in size and is managed by the Bureau of Land Management (BLM). The California Desert Protection Act of 1994 created the Sylvania Mountains Wilderness and was added to the National Wilderness Preservation System. The wilderness is bordered by Nevada stateline on the east, Piper Mountain Wilderness on the west and Death Valley National Park to the south.
The Santa Rosa Wilderness is a 72,259-acre (292.42 km2) wilderness area in Southern California, in the Santa Rosa Mountains of Riverside and San Diego counties, California. It is in the Colorado Desert section of the Sonoran Desert, above the Coachella Valley and Lower Colorado River Valley regions in a Peninsular Range, between La Quinta to the north and Anza Borrego Desert State Park to the south. The United States Congress established the wilderness in 1984 with the passage of the California Wilderness Act, managed by the both US Forest Service and the Bureau of Land Management. In 2009, the Omnibus Public Land Management Act was signed into law which added more than 2,000 acres (8.1 km2). Most of the Santa Rosa Wilderness is within the Santa Rosa and San Jacinto Mountains National Monument.
The Colorado River is a major river of the western United States and northwest Mexico in North America. Its headwaters are in the Rocky Mountains where La Poudre Pass Lake is its source. Located in north central Colorado it flows southwest through the Colorado Plateau country of western Colorado, southeastern Utah and northwestern Arizona where it flows through the Grand Canyon. It turns south near Las Vegas, Nevada, forming the Arizona–Nevada border in Lake Mead and the Arizona–California border a few miles below Davis Dam between Laughlin, Nevada and Needles, California before entering Mexico in the Colorado Desert. Most of its waters are diverted into the Imperial Valley of Southern California. In Mexico its course forms the boundary between Sonora and Baja California before entering the Gulf of California. This article describes most of the major features along the river.
Sand to Snow National Monument is a U.S. National Monument located in San Bernardino County and into northern Riverside County, Southern California.
