Llano Estacado

Llano Estacado (, (meaning Palisaded Plains), commonly known as the Staked Plains, is a region in the Southwestern United States that encompasses parts of eastern New Mexico and northwestern Texas, including the South Plains and parts of the Texas Panhandle. One of the largest mesas or tablelands on the North American continent, the elevation rises from 3000 ft in the southeast to over 5000 ft in the northwest, sloping almost uniformly at about 10 ft/mi.  At such a gradual slope, however, the elevation change is imperceptible to the observer.

Geography and climate
The Llano Estacado lies at the southern end of the High Plains section 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 ft high, lies between the Llano and the red Permian plains of Texas; while to the west, the Mescalero Escarpment demarcates the 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 mi north to south, and 150 mi east to west, a total area of some 37500 sqmi, larger than Indiana and 12 other states. It covers all or part of thirty-three Texas counties and four New Mexico counties.

Spanish conquistador Francisco Coronado, the first European to traverse this "sea of grass" in 1541, described it as follows: "I reached some plains so vast, that I did not find their limit anywhere I went, although I travelled over them for more than 300 leagues ... with no more land marks than if we had been swallowed up by the sea ... there was not a stone, nor bit of rising ground, nor a tree, nor a shrub, nor anything to go by."

After his 1852 expedition to explore the headwaters of the Red and Colorado rivers, General Randolph Marcy agreed: "[not] a tree, shrub, or any other herbage to intercept the vision... the almost total absence of water causes all animals to shun it: even the Indians do not venture to cross it except at two or three places." The landscape is, however, dotted by numerous small playa lakes, depressions that seasonally fill with water and provide important habitat for waterfowl.

The Llano Estacado has a semiarid climate (Köppen Bsk), characterized by long hot summers and cold winters. Rainfall is extremely low; the entire region receives fewer than 23 in of rainfall annually, and the western part receives as little as 14 in. High summer temperatures (average July temperature above 85 F) mean that most of the small amount of precipitation is lost to evaporation, making dry-land farming extremely difficult.

The Llano Estacado is one of the largest cotton-producing regions of the United States.

Water used today in agriculture on the Llano today is brought to the surface by electric pumps. Before electricity, large ranches grazed cattle, but that soon destroyed the fragile grasses.

The scanty rainfall simply evaporates or disappears into the porous soil and cannot refill the aquifer at the rate it is being depleted. There are no nearby sources of abundant water. The Pecos runs nearly dry from irrigation diversions.

Monument Spring, a permanent oasis not far from Hobbs, New Mexico, was one of the rare watering places. The "monument" was a pile of caliche raised by Native Americans to guide people to the spot.

History and name
Coronado named the region after seeing the cliffs of the Caprock Escarpment from the north on his way east from Cíbola. They appeared to be an impenetrable defense for the land, and he called it Llano Estacado, Spanish for "Palisaded Plains." The name is often mistranslated as "staked plain," giving rise to fanciful stories to explain it. Some allude to yucca stems, others to stakes driven into the ground as landmarks, and still others to similar, even less plausible objects. None of these has been proven the reason for the name.

The conquistadors reintroduced horses to the Great Plains since their extinction in North America eons earlier. Some horses escaped and bred in the wild. The Native American tribes of the Plains captured horses and integrated their use into their cultures in the succeeding centuries. Having horses allowed them to expand their territories and hunting grounds. Before this, the dog was their largest domesticated animal.

In the early 18th century, the Comanches expanded their territory into the Llano Estacado, displacing the Apaches who had previously lived there. The region became part of the Comancheria, a Comanche stronghold until the final defeat of the tribe in the late 19th century.

In the latter part of the 19th century, the Llano was a refuge for the bands of Kiowas and Comanches who did not wish to be cooped up on reservations in Indian Territory in present-day Oklahoma. One of their last battles against the US Army was fought in bitter cold on 2 December 1874 in Palo Duro Canyon. The waterless region was very difficult for the U.S. Cavalry to function. The Native Americans could disappear into the slight draws of the featureless expanse, or into the labyrinths of canyons such as Palo Duro.

Because of the lack of surface water, low rainfall, and the harsher climate, the Llano was one of the last areas to be settled and farmed by European Americans in contemporary Texas. Better well-drilling technology by the late 1910s to 1920s was responsible for the maintenance and growth of many oil caprock towns. However, because of overuse of the underground aquifer, since the 1970s, the economy has depended on farmers' returning to dryland crops.

Human population
Because of its difficult conditions, the Llano Estacado has an extremely low population density, as can be seen in the map. Most of the area's population is localized in the principal cities of Amarillo, Lubbock, Midland and Odessa, Texas. The vast majority of the area is rural, covered by large ranches and irrigated farms. Several small- to medium-sized towns do exist, however, including Andrews, Hereford, Plainview, Levelland, and Lamesa, Texas, and Clovis and Hobbs, New Mexico.

The Llano Estacado is larger in area than New England. The southern extension of the High Plains, the region is some 250 miles north to south and 200 miles east to west. The roads are straight and meet mostly at right angles. Cotton is an essential crop with irrigation, but faces declining prices at times on the world market. The Llano Estacado is sometimes humorously described as "85 percent sky and 15 percent grassland."

For years, the Llano Estacado was isolated from the state government in Austin and the national leadership in Washington, D.C., though powerful lawmakers, such as George H. Mahon, Kent Hance, and Robert L. Duncan emerged to defend its interests. The area has a large number of churches per capita. Lubbock, known for a wide variety of denominations, also holds the distinction of being the most populous city on the High Plains from the Dakotas through Texas. Prohibition did not end on the Texas Plains in 1933 with repeal of the Eighteenth Amendment to the United States Constitution, but continued for years at the county level. Even in 2010, some forty Texas counties, most in the Llano Estacado, remain officially "dry" to the sale of alcohol.

Geology
The Ogallala Group is a late Tertiary (Pliocene) sheet of sediments spread over the area east of the Rocky Mountains from Wyoming to Texas, rather recently in a geological sense, when the Colorado Plateau and Rocky Mountain regions were elevated from near sea level to about their current elevations. The eroded sediments (mainly earlier Tertiary rocks) spread over the low plains to the east. The Ancestral Rocky Mountains had been formed much earlier, at the end of the Cretaceous and the beginning of the Tertiary eras, and had been worn down to near flatness before the late Tertiary uplift. In the northern areas, the Ogallala was spread over earlier Tertiary and Cretaceous rocks. In the Llano Estacado, erosion had removed everything down to the Triassic, and even to the Permian redbeds. At the southern end, some Cretaceous limestone remained, however. The Ogallala was laid down over all of this by lazy, sandy streams near sea level, which produced the flatness of its surface. Subsequently, the uplift in the west progressed to the east, raising and tilting the Ogallala surface to its present position, and changing the environment from depositional to erosional. Some major rivers, such as the Pecos and Canadian, incised their courses deeply as the region was elevated, while others, such as the Red, Brazos, and Colorado rivers, arose on the dip slope. The erosion of these rivers has now defined the area of the Llano Estacado, separating it from its Rocky Mountain sources and from other parts of the High Plains.

Other areas of the Ogallala surface, or High Plains, have the same history. In Wyoming, it is still in contact with the mountains west of Cheyenne (the "Gangplank"), but elsewhere it is separated from the mountains by valleys of Cretaceous and earlier rocks due to active erosion at these higher levels. Only in the Llano Estacado area has the formation of the Caprock given rise to a prominent, distinctive, palisade-like escarpment, as well as to a remarkably flat surface. Further north, rivers such as the Platte, Arkansas, and Cimarron have sliced it into segments.

Another distinctive characteristic is that the surrounding rocks are often red, as in Palo Duro Canyon, making a striking contrast with the light-colored rocks of the plateau. In some other places, the erosional edge of the High Plains is marked by "breaks" or other abrupt changes of scenery, as in eastern Wyoming and western Nebraska. In these areas, the High Plains are usually sandy, rolling plains with normal, branching drainage, not flat surfaces without continuous streams.

Hydrogeology
The "bedrock" of the plain is the indurated top of the Ogallala Group, a hard caliche layer called the Caprock. This was formed when surface drying caused mineral-laden water to rise by capillary action to the surface. Evaporating, the minerals were left behind to cement the otherwise fairly loose sandy sediments of the Ogallala Group. The Caprock is generally covered by sands and soils. Where soils predominate, the land is fertile when irrigated, and is devoted to field crops, including grain and cotton. Irrigation water is mined from the deeper parts of the Ogallala Group by electric pumps, since there is almost no usable surface water. As the pumped water is being used much more rapidly than it is replenished, eventually Llano farmers will be forced to employ dryland cropping systems or return the area to its natural state of sparse grassland.

Other meanings

 * Llano Estacado Winery is a winery located near Lubbock, Texas.
 * "El Llano Estacado" is a traditional folk song adapted by Tom Russell.