Prehistoric North America was home to a numerous and diverse array of peoples, languages, religions, and cultures. Scientific origin theories such as the Bering Land Bridge and the Solutrean hypothesis suggest that the ancestors of these groups arrived in the Western hemisphere at least 14,000 years ago. The origin stories of most of the groups take another view, stressing the intimate relationship between “the people” and the land they lived in; many origin stories state that the land was created exclusively for the group. The earliest groups in the Americas are referred to as Paleo-Indians. Clovis points are one of the most important and closely identified artifacts with the Paleo-Indian era. Changes in the global climate helped to bring the Paleo-Indian period to an end. The death of the megafauna meant that humans had to find new means of subsistence. The Archaic and Woodland periods, the archaeological periods following the Paleo-Indian, are characterized by the development of plant domestication and the beginnings of organized agricultural activities. Many of the groups of North America became agriculturalists, relying primarily on the Mesoamerican triad of corn, beans, and squash. The surplus of food from agriculture enabled the development of complex towns and cities such as the Mississippian Cahokia settlement. Regional geography also played a role in shaping groups; for instance, groups on the Plains came to be characterized by relying on the buffalo as a main source of food and resources for subsistence.
The Native American world that Europeans contacted after 1492 was complex, highly developed, and rich in oral history. The period of contact between Europeans and hundreds of native groups played an important role in shaping American colonies and nations, the United States among them. From the very beginning, Indians played a pivotal role in shaping the future of the nation.