The Western United States, commonly referred to as the American West or simply the West," traditionally refers to the region comprising the westernmost states of the United States. Because the U.S. expanded westward after its founding, the meaning of the West has evolved over time. Prior to about 1800, the crest of the Appalachian Mountains was seen as the western frontier. Since then, the frontier moved further west and the Mississippi River was referenced as the easternmost possible boundary of the West.
The West mostly comprises arid to semi-arid plateaus and plains and forested mountains.
Monument Valley (Navajo: Tsé Biiʼ Ndzisgaii, meaning valley of the rocks) is a region of the Colorado Plateau characterized by a cluster of vast sandstone buttes, the largest reaching 1,000 ft (300 m) above the valley floor. It is located on the Arizona-Utah state line (around 36°59′N110°6′W / 36.983°N 110.100°W / 36.983; -110.100), near the Four Corners area. The valley lies within the range of the Navajo Nation Reservation, and is accessible from U.S. Highway 163.
Director John Ford used the location for a number of his best known films, and thus, in the words of critic Keith Phipps, "its five square miles have defined what decades of moviegoers think of when they imagine the American West."