The Llano Estacado, sometimes translated into English as the Staked Plains, is a region in the Southwestern United States that encompasses parts of eastern New Mexico and northwestern Texas. One of the largest mesas or tablelands on the North American continent, the elevation rises from 3,000 feet (900 m) in the southeast to over 5,000 feet (1,500 m) in the northwest, sloping almost uniformly at about 10 feet per mile (2 m/km).

The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that includes Arizona and New Mexico, along with adjacent portions of California, Colorado, Nevada, Oklahoma, Texas, and Utah. The largest cities by metropolitan area are Phoenix, Las Vegas, El Paso, Albuquerque, and Tucson. Before 1848, in the historical region of Santa Fe de Nuevo México as well as parts of Alta California and Coahuila y Tejas, settlement was almost non-existent outside of Nuevo México's Pueblos and Spanish or Mexican municipalities. Much of the area had been a part of New Spain and Mexico until the United States acquired the area through the Treaty of Guadalupe Hidalgo in 1848 and the smaller Gadsden Purchase in 1854.