Answer:
Although the land that now constitutes the United States was occupied and much affected by diverse Indian cultures over many millennia, these pre-European settlement patterns have had virtually no impact upon the contemporary nation—except locally, as in parts of New Mexico. A benign habitat permitted a huge contiguous tract of settled land to materialize across nearly all the eastern half of the United States and within substantial patches of the West. The vastness of the land, the scarcity of labour, and the abundance of migratory opportunities in a land replete with raw physical resources contributed to exceptional human mobility and a quick succession of ephemeral forms of land use and settlement. Human endeavours have greatly transformed the landscape, but such efforts have been largely destructive. Most of the pre-European landscape in the United States was so swiftly and radically altered that it is difficult to conjecture intelligently about its earlier appearance.