Colorado Plateau, physiographic region of SW North America, c.150,000 sq mi (388,500 sq km), in Arizona, Utah, Colorado, and New Mexico, including the "Four Corners" area. It is characterized by broad plateaus, ancient volcanic mountains at elevations of c.5,000 to 13,000 ft (1,520–3,960 m), and deeply dissected canyons lined with often brightly colored sedimentary and volcanic rocks, including the Grand Canyon of the Colorado River. Native American reservations occupy about one third of the mostly semiarid and sparsely vegetated area, which was the last U.S. region to be explored by whites. About one half of the public land is used for grazing. Among many ancient cliff dwellings are those at Mesa Verde and Canyon de Chelly. The region has a number of U.S. national parks and monuments.
See K. A. Brown, Four Corners (1996).