The archaeological record of the first Americans in Mexico is poorly known and somewhat confusing. However, the state of Sonora presents a remarkably pristine setting for studying the late Pleistocene occupation of North America. The early archaeological record in Sonora is stunning in terms of its relative abundance and only within the past ten years has this fact become evident. The Paleo-Indian sites are concentrated in north-central Sonora on and surrounding, the Llanos de Hermosillo. The settlement pattern appears to indicate that Clovis groups were generalized hunter and gatherers that exploited a wide range of environments, and their diet was based upon a wide variety of foodstuffs. The Clovis groups of Sonora developed a sophisticated settlement pattern and land use determined by the location of lithic sources for tool making, water sources, large prey animals and a mosaic of edible plants and small animals. Exploiting an extensive territory probably permitted them to remain in the same region for longer periods of time. The presence of only few late Paleo-Indian diagnostic points could represent the decrease of population density in Sonora, but most likely it is an indication that after Clovis a regionalization of the hunter and gather groups took place in Sonora. The Sonoran Clovis occupation is a testimony that multiple regional Clovis adaptations emerged each with specific responses of plants, animals and resources.