Thousands of Plains farmers settled along Ponca creek in northeastern Nebraska during the latter decades of the 13th century, in the midst of a wave of social change and dislocation across the mid-continent as Cahokia collapsed and drought spread widely over much of North America. In contrast to the small homesteads on the central Plains prior to this time, the Ponca creek sites range up to 200 acres, suggesting a community bigger than anything that had existed in the region before. Potters at the site made classic Plains vessels and classic midwestern Oneota vessels in households that were nearly side-by-side and mixed these styles together on other pots. This lecture addresses the social changes at work in the mid-continent at this time along with the history of work on Ponca creek from the 1930s to the present, including geophysical prospecting and excavation in the last few years. Viewed in the context of the Plains as a whole, the changes there represent a sea-change in social formations and likely mark the appearance of the modern Pawnee and Arikara nations.