When Did the First People Arrive?
It is difficult to know for certain when people first journeyed south from Beringia into North and South America. The most widely accepted view is that the migration began sometime between 15,000 and 12,000 years ago, toward the end of the last Ice Age. By that time, the climate had begun to warm and the vast ice sheets that blocked passage across Canada had begun to recede.
Scientists have two ideas about how could have people traveled beyond the ice sheets that covered Canada and blocked access to the United States. One idea proposes that an ice free corridor opened in Canada as the glaciers melted. According to this theory, small trees began to appear in the ice-free corridor and, for the first time, wood became available for the warmth and cooking fires people needed to survive the journey. The second idea suggests that people migrated down the coastline. Although the coastline was not completely ice-free, people may have used boats, and driftwood might have supplied the fires needed for survival.
Recently, a new theory has challenged the prevailing view about when people first migrated to the Americas.