Monument Valley (Navajo: Tsé Bii' Ndzisgaii, meaning valley of the rocks) is a region of the Colorado Plateau characterized by a cluster of vast sandstone buttes, the largest reaching above the valley floor. It is located on the Arizona-Utah state line (around ), near the Four Corners area. The valley lies within the range of the Navajo Nation Reservation and is accessible from U.S. Highway 163.