The leading theory regarding how early humans arrived in the Americas is known as the "Beringia" or "Bering Land Bridge" theory. This theory posits that during the last Ice Age, approximately 20,000 to 15,000 years ago, lower sea levels exposed a land bridge between Asia and North America called Beringia. This land bridge connected what is now Alaska and Siberia, allowing prehistoric humans to migrate from Asia into the Americas.
Once across this land bridge, these early inhabitants gradually moved southward into various parts of North America and eventually into Central and South America. Archaeological evidence, including tools and artifacts, supports this migration route.
While the Beringia theory has been the dominant explanation, researchers also consider alternative routes, such as coastal migration along the Pacific shoreline, and there is ongoing research into the timing and routes of these migrations, with some evidence suggesting that human presence in the Americas may have predated the widespread acceptance of the Beringia model. Nevertheless, the Bering Land Bridge remains a central component of our understanding of early human migration to the Americas.