Great American Desert
The area is now usually referred to as the High Plains, and the original term is now sometimes used to describe the arid region of North America, which includes parts of northern Mexico and the American southwest.
The concept of "desert" 
In colonial times, the term "desert" was often used to describe treeless or uninhabited lands whether they were arid or not. By the 19th century, the term had begun to take on its modern meaning. It was long thought that treeless lands were not good for agriculture; thus the term "desert" also had the connotation of "unfit for farming". While the High Plains are not a desert in the modern sense, in this older sense of the word they were. The region is mostly semi-arid grassland and steppe. Today much of the region supports agriculture through the use of aquifer water irrigation. But in the 19th century, the area's relative lack of water and wood made it seem unfit for farming and uninhabitable by an agriculturally-based people.
When the region was obtained by the United States as part of the Louisiana Purchase in 1803, President Jefferson wrote of the "immense and trackless deserts" of the region. Zebulon Pike wrote "these vast plains of the western hemisphere, may become in time equally celebrated as the sandy deserts of Africa". His map included a comment in the region, "not a stick of timber". In 1823, Major Stephen Long, a government surveyor and leader of the next official exploration expedition, produced a map labeling the area the Great American Desert. In the report that accompanied the map, the party's geographer Edwin James wrote of the region:
I do not hesitate in giving the opinion, that it is almost wholly unfit for cultivation, and of course, uninhabitable by a people depending upon agriculture for their subsistence. Although tracts of fertile land considerably extensive are occasionally to be met with, yet the scarcity of wood and water, almost uniformly prevalent, will prove an insuperable obstacle in the way of settling the country.
While many other travelers reported similar conditions and conclusions, there were problems in the interpretation and the use of the word "desert". By the 19th century, the word had begun to assume its modern sense, evoking images of sandy wastelands. Yet descriptions of the American High Plains almost always included comments about "Innumerable Herds of Buffaloes", which was written on Pike's map just above "not a stick of timber". The giant herds and teeming wildlife of the Great Plains were well known by the time the term Great American Desert came into common use, undermining the idea of a wasteland; however, the relevant concept inherent in the reports of the region was that it could not be farmed, something the reports generally agreed on. By the middle of the 19th century, as settlers migrated across the plains to Oregon and California, the wasteland connotation of "desert" was seen to be false, but the sense of the region as uninhabitable remained until irrigation, railroad transportation, and barbed wire made up for the lack of surface water and wood.
Settlement and development 
The region's relative lack of water and wood affected the development of the United States. Settlers heading westward often attempted to pass through the region as quickly as possible en route to what was considered to be better land farther west. These early settlers gave telling names to the various streams of the region, such as "Sweetwater Creek" or "Poison Creek". Because it was not considered desirable, the area became one of the last strongholds of independent American Indians. Railroad interests seeking rights-of-way through the region also benefited from the popular belief that the land was commercially valueless.
By the mid-19th century, people had begun settling in the region despite its poor reputation. The local inhabitants came to realize the area was at the time well suited for farming, due in part to the fact that large portions of the region sit atop one of the world's largest underground reservoirs, the Ogallala Aquifer. Experts of the era proposed theories that maintained the earlier reports had been accurate and the climate had changed. Some even credited the settlers themselves as having caused the change by planting crops and trees. The slogan "rain follows the plow" was created to describe this belief. Today these theories are discredited.
Additionally, it has been demonstrated that while there is an abundant amount of water in the Ogallala Aquifer, it is slow to replenish itself, with most of the water in the Aquifer having been there since the last Ice Age. Some current estimates predict the usefulness of the Aquifer for agriculture to subside and be useless as soon as the early parts of the mid-21st century, leading current farmers to turn away from irrigated agriculture using the aquifer.
See also 
- Darton, N.H. 1920. Syracuse-Lakin folio, Kansas. United States Department of the Interior, U.S. Geological Survey, Folios of the Geologic Atlas, No. 212, 10 pp. (See Plate 2)
- Meinig, D.W. (1993). The Shaping of America: A Geographical Perspective on 500 Years of History, Volume 2: Continental America, 1800-1867. New Haven: Yale University Press. ISBN 0-300-05658-3; pg. 76
- "Ogallala aquifer - Water hot spots". BBC News. ?.