Between approximately 3,500 and 1,800 years before present, indigenous societies inhabiting southeastern Minnesota experienced a profound cultural transformation. During this time, a combination of environmental changes, technological innovations and socio-cultural shifts stimulated lifeway alterations among people of the Archaic Tradition to those of the Woodland Tradition. This unique natural region developed from a complex sequence of climatic, geomorphic, and vegetational events with a variety of resources that offered a favorable location for human occupation. Mobile and dispersed Late Archaic groups utilized a more or less balanced admixture of upland and lowland resources. Near the end of the Late Archaic period important resources were becoming depleted from packed populations resulting in less mobility, territorial claims and increased conflict. As a result, subsistence began to shift to more localized use of domesticated and wild plants and aquatic resources. Groups began congregating in lowland settings and increased their reliance on stored foods. A change in climate likely exacerbated the subsistence, settlement and sociocultural shifts. A significant climate change occurring between ca. 3,500 and 3,000 BP influenced the vegetation patterns and modified the landscape. The prairie border shifted westwards, replaced with oak savanna and increased mast production and deer habitat. Along the Mississippi Trench and larger tributary streams, dramatic increases in flooding rejuvenated floodplains, increased overall productivity, and created environments conducive for pioneer plant species that were used for food by the Late Archaic and Early Woodland inhabitants. Such flooding may have disturbed lifeway routines in lowland settings by disrupting access to resources and resource production for prolonged periods. In the uplands, snowier conditions may have caused declines in resources (e.g., deer, hides) and hunting access. In response, use of aquatic and plant resources increased during the Early Woodland, where a shift to more lowland resources is evident. Populations congregated in semi-sedentary to sedentary settlements in river valleys. Territorialism, conflict, and the use of stored foods were intensified. Technological changes included the adoption of ceramics allowing for more efficient plant food processing. Egalitarianism gave way to hierarchies and ceremonialism may have increased. Following these adjustments, groups archaeologically identified as Early Woodland emerged.