Did ancestral Native Americans first enter the Americas during the Last Glacial Maximum around 21,000 years ago?

A serious early-arrival interpretation holds that humans may have reached the Americas before or during the Last Glacial Maximum, potentially after occupying Beringia and using routes later blocked or altered by ice. Its strongest support comes from chronological models and broader evidence for pre-Clovis occupation, but the interpretation depends on disputed sites and dating assumptions.

• A Bayesian analysis of archaeological dates concluded that humans were probably present before, during, and immediately after the Last Glacial Maximum.
• The Beringian Standstill model links ancestral Native Americans to a population occupying Beringia during the Last Glacial Maximum, with evidence that humans lived there before 30,000 years ago.
• Some reviews argue that preglacial occupation should be closely examined and that several routes may have been available late in the last glacial cycle.
• Critics contend that the evidence for pre-Last Glacial Maximum occupation, including disputed lithic finds, does not securely demonstrate human activity.

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