Who first migrated to and populated the americas over 13,000 years ago?

The first populations of North and South America arrived between 10,000 and 20,000 years ago, traveling across the Beringia land bridge between Siberia and western Alaska. These were hunter-gatherers from North Asia referred to as the Paleo-Indians. It is thought that the first groups, or "Clovis cultures", arrived around 13,000 years ago, though discoveries in the early 2000's of precursors to the Clovis groups have pushed that figure back closer to 16,000-20,000 years ago.