In 1528, the Spanish explorer Alvar Nunez Cabeza de Vaca and his three companions were shipwrecked and, looking for help, began an eight-year trek through the deserts of the American West. Over three centuries later, the four "Great Surveys" in the United States were consolidated into the U.S. Geological Survey.

The frontiers were the lands near or beyond the recognized international, national, regional, or tribal borders. Over the centuries, they hosted a complicated series of international explorations of lands inhabited by American Indians, Spanish, French-Canadians, British, and Americans. These explorations were undertaken for wide-ranging reasons including geographical, scientific, artistic-literary, and for the growth of the railroad. This history covers over 350 years of exploration of the West.