Llano Estacado

The Llano Estacado (Spanish: [ˈʝano estaˈkaðo]), 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 Spanish name Llano Estacado is often interpreted as meaning "Staked Plains", although "stockaded" or "palisaded plains" have also been proposed, in which case the name would derive from the steep escarpments on the eastern, northern, and western periphery of the plains. Leatherwood writes that Francisco Coronado and other European explorers described the Mescalero Ridge on the western boundary as resembling "palisades, ramparts, or stockades" of a fort, but does not present the original Spanish. In Beyond the Mississippi (1867), Albert D. Richardson, who traversed the region from east to west in October 1859, wrote that "the ancient Mexicans marked a route with stakes over this vast desert, and hence its name." Other sources refer to "stakes" used to mark routes on the featureless plain, often meaning piles of stone, bone, and cow dung. According to Place Names of New Mexico, others have speculated that "stakes" refers to the yucca plants that dot the plains. Leatherwood opines in the Handbook of Texas that such way markers could plausibly explain the origin of the name, but that the "comparison of cliff formations and palisades made by explorers argues more convincingly for the geological origin". In his Roadside Geology of Texas, Geologist Darwin Spearing also prefers the geological solution to the etymology:

The 'Staked Plains' tale is deeply entrenched in Texas mythology, but the real interpretation of Llano Estacado is sensible geologic: it means 'stockaded' or 'palisaded' plains - which is precisely how the edge of the plains appear when viewed from below the caprock.

The Llano Estacado lies at the southern end of the Western High Plains ecoregion of the Great Plains of North America; it is part of what was once called the Great American Desert. The Canadian River forms the Llano's northern boundary, separating it from the rest of the High Plains. To the east, the Caprock Escarpment, a precipitous cliff about 300 feet (100 m) high, lies between the Llano and the red Permian plains of Texas; while to the west, the Mescalero Escarpment demarcates the eastern edge of the Pecos River valley. The Llano has no natural southern boundary, instead blending into the Edwards Plateau near Big Spring, Texas. This geographic area stretches about 250 miles (400 km) north to south, and 150 miles (240 km) east to west, a total area of some 32,000 square miles (83,000 km²), larger than Indiana and 12 other states. It covers all or part of 33 Texas counties and four New Mexico counties. The area is susceptible to frequent dust storms because of its low relief, frequent turbulent winds, lack of vegetation, and loose topsoil. The landscape is dotted by numerous small playa lakes, depressions that seasonally fill with water and provide habitat for waterfowl.

The Llano Estacado has a cold semiarid climate (Köppen BSk), characterized by long, hot summers and cold winters. Rainfall is relatively low; the entire region receives fewer than 23 in (580 mm) of rainfall annually, and the western part receives as little as 14 in (360 mm). High summer temperatures (average high July temperature above 90 °F or 32 °C) mean that most of the small amount of precipitation is lost to evaporation, making dryland farming difficult.

As the Llano Estacado lies on the western edge of Tornado Alley, supercell thunderstorms capable of producing large, violent tornadoes and destructive hailstorms are common in spring and autumn.

The Texas State Historical Society states it covers all or part of 33 Texas counties, six fewer than as depicted by a US Geological Survey map, and four New Mexico counties.

As depicted by a US Geological Survey map, the Llano Estacado includes all or part of these Texas counties: