<P> Phoenix is the largest metropolitan area of the Mountain States, followed by Denver, Las Vegas, and Salt Lake City . </P> <P> The Mountain West is one of the largest and most diverse regions in the United States . Most regional boundaries of the Mountain West are often looked at as the area from the High Plains to the Sierra Nevada and Cascade Range . The southern and northern portions of the Mountain West are often split into two separate regions . The southern portion (Arizona and New Mexico) is often called the Southwest region, while the northern portion (Idaho and Montana) is often included in either the Northwest states or called the Northern Rockies . The land area of the eight states together is some 855,767 square miles (2,216,426 square kilometres). </P> <P> The terrain of the Mountain West is more diverse than any other region in the United States . Its physical geography ranges from some of the highest mountain peaks in the continental United States, to large desert lands, and rolling plains in the eastern portion of the region . The Mountain West states contain all of the major deserts found in North America . The Great Basin Desert is located in almost all of Nevada, western Utah, and southern Idaho . Portions of the Mojave Desert are located in California, but over half of the desert is located in southern Nevada, in the Mountain West . Meanwhile, the Sonoran Desert is located in much of Arizona, and the Chihuahuan Desert is located in most of southwestern and southern New Mexico, including White Sands and Jornada del Muerto . Colorado also has scattered desert lands in the southern and northwestern portions of the state including the expansive San Luis Valley . </P> <P> Colorado, New Mexico, Utah, and Arizona have other smaller desert lands, part of the Colorado Plateau . The Painted Desert is located in northern and northeastern Arizona, and the San Rafael Desert is located in eastern Utah . New Mexico has other desert lands located in the northern and northwest . Colorado has large desert lands on the Colorado plateau in the northwestern, western, and southern parts of the state . These desert lands in Colorado are located in and around areas such as Royal Gorge, Great Sand Dunes National Park, Pueblo, the San Luis Valley, Cortez, Dove Creek, Delta, Canyons of the Ancients National Monument, the Roan Plateau, Dinosaur National Monument, Colorado National Monument, and the Grand Mesa . The San Luis Valley is the largest high valley desert in the world . </P>

Why do the mountain states have some of the highest elevations in the west
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