Most historical studies of migration in the Americas focus either on North America or South (Latin) America or on a few countries (Canada, Argentina, the United States) that have made immigration central themes in national histories. This essay instead offers a very long-term perspective on migrations in the hemispheric Americas. It draws on world historians’ analysis of archaeological, genomic and historical linguistic evidence to describe pre-historic movements, on historians of the early modern Atlantic and modern era of migrations from Europe and Asia, and on social science studies of contemporary migrations into and around the Americas. Social scientists studying the most recent migrations are far more likely than historians to emphasize their unprecedented size and significance. While historians agree that the origins and destinations of recent migrants in the Americas are more diverse than in the past, they otherwise view recent migrations as the latest phase in a long history of human mobility, with social, economic and cultural transformations differing only modestly from those of the past.