Monument Valley is located on the southern border of Utah with northern Arizona (around [show location on an interactive map] 36°59′N, 110°6′W). The valley lies within the range of the Navajo Nation Reservation, and is accessible from U.S. Highway 163. The Navajo name for the valley is Tsé Bii’ Ndzisgaii (Valley of the Rocks).
Monument Valley
Geology
The area is part of the Colorado Plateau. The floor is largely Cutler Red siltstone or its sand deposited by the meandering rivers that carved the valley. The valley’s vivid red color comes from iron oxide exposed in the weathered siltstone. The darker, blue-gray rocks in the valley get their color from manganese oxide.