The first people to arrive in the Americas are believed to have been nomadic hunters and gatherers who followed herds of animals across the land bridge. They likely crossed from Asia into North America around 15,000 to 13,000 years ago when the Bering Land Bridge was at its widest.
Once in North America, these early people spread out and eventually populated the entire continent. They developed different cultures and ways of life, and their descendants became the indigenous peoples of the Americas.
There is some evidence to suggest that there may have been other, earlier migrations to the Americas, but the Bering Land Bridge is the most widely accepted theory of how the first people arrived in the Americas.