The Earth sciences have played a key role in understanding the origins and subsequent development of the first American cultures (“Paleoindians”), a broad and often contentious topic in archaeology. Geoarchaeological approaches used to understand the peopling of North America are equally broad at a range of spatial scales. At subcontinental scales, geoarchaeological research revolves around lowered seas levels and fluctuating glacier margins. Modeling sea‐level changes and the high‐precision dating of ice retreat over Canada is helping to understand the environmental conditions, route(s), and timing of the earliest human entry into and colonization of North America. Stratigraphy, a fundamental principle in both archaeology and geology, first established the antiquity and chronology of the earliest artifact assemblages by demonstrating clear association of artifacts and Pleistocene fauna. Many Paleoindian sites also yielded stratigraphic records with evidence of markedly different depositional environments in the past. The ancient fauna and the striking contrasts between past and present depositional environments has long attracted the attention of archaeologists and Earth scientists alike because of the paleoenvironmental implications. Reconstructing the evolution of paleo‐lakes and paleo‐wetlands is aiding in the understanding of ancient landscapes and their evolution. These landscape‐scale studies and micromorphology also provide insights into Paleoindian subsistence.