<P> The term Great American Desert was used in the 19th century to describe the western part of the Great Plains east of the Rocky Mountains in North America to about the 100th meridian . </P> <P> 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 northwestern Mexico and the American southwest . </P> <P> 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 . </P> <P> 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: </P>

Why was it called the great american desert
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