Nearly one billion people today call the Americas home, inhabiting territories that stretch from the wide expanses of Canada and the United States, down through Mexico and Central America, and south through the varied landscapes of South America to Chile—from sparsely populated regions to some of the most crowded cities on the planet. And yet, as recently as 16,000 years ago, there may not have been anyone in these lands at all. Who were the earliest Americans, and how and when did they get here? These are questions that have long fascinated archaeologists and the public alike. As with all scientific endeavors, uncovering the story of how and when people arrived in the Americas will require an accumulation of evidence and data, and will long continue to be subject to revision. Here, then, is where the research has led so far: