<P> West of the Rocky Mountains lies the Intermontane Plateaus (also known as the Intermountain West), a large, arid desert lying between the Rockies and the Cascades and Sierra Nevada ranges . The large southern portion, known as the Great Basin, consists of salt flats, drainage basins, and many small north - south mountain ranges . The Southwest is predominantly a low - lying desert region . A portion known as the Colorado Plateau, centered around the Four Corners region, is considered to have some of the most spectacular scenery in the world . It is accentuated in such national parks as Grand Canyon, Arches, Mesa Verde National Park and Bryce Canyon, among others . Other smaller Intermontane areas include the Columbia Plateau covering eastern Washington, western Idaho and northeast Oregon and the Snake River Plain in Southern Idaho . </P> <P> The Intermontane Plateaus come to an end at the Cascade Range and the Sierra Nevada . The Cascades consist of largely intermittent, volcanic mountains, many rising prominently from the surrounding landscape . The Sierra Nevada, further south, is a high, rugged, and dense mountain range . It contains the highest point in the contiguous 48 states, Mount Whitney (14,505 ft or 4,421 m). It is located at the boundary between California's Inyo and Tulare counties, just 84.6 mi or 136.2 km west - northwest of the lowest point in North America at the Badwater Basin in Death Valley National Park at 279 ft or 85 m below sea level . </P> <P> These areas contain some spectacular scenery as well, as evidenced by such national parks as Yosemite and Mount Rainier . West of the Cascades and Sierra Nevada is a series of valleys, such as the Central Valley in California and the Willamette Valley in Oregon . Along the coast is a series of low mountain ranges known as the Pacific Coast Ranges . Much of the Pacific Northwest coast is inhabited by some of the densest vegetation outside of the Tropics, and also the tallest trees in the world (the Redwoods). </P> <P> Alaska contains some of the most dramatic and untapped scenery in the country . Tall, prominent mountain ranges rise up sharply from broad, flat tundra plains . On the islands off the south and southwest coast are many volcanoes . Hawaii, far to the south of Alaska in the Pacific Ocean, is a chain of tropical, volcanic islands, popular as a tourist destination for many from East Asia and the mainland United States . </P>

How much of the us is covered by mountains