A rchaeology has a long history dealing with population demography. Many re- searchers have tackled the issue of local population size, or the population of a region, as an objective in its own right. Others have worked to reconstruct figures of past population numbers, demography, and population fluctuations across time and space as critical factors that played a role in social and historical developments. Despite the diversity of archaeological research today, it has been argued that a consideration of population dynamics is crucial for understanding a vast num- ber of research problems dealing with cultural change (e.g., Cobb 2005; Milner 1998; Milner and Chaplin 2010; Muller 1993, 1997a; Pauketat 2003; Shennan 2000). With continued advancements in chronometric dating, archaeologists are now more able than ever to track population dynamics, short-term de- mographic events, and population movements across landscapes. Greater chronological preci- sion has served to increase knowledge concerning SHIFTING COMMUNITIES: DEMOGRAPHIC PROFILES OF EARLY VILLAGE POPULATION GROWTH AND DECLINE IN THE CENTRAL AMERICAN BOTTOM Casey R. Barrier and Timothy J. Horsley The growth and decline of large village communities is a topic of considerable interest for archaeologists studying the devel- opment of complex regional polities. In this article, demographic information is presented for the transitional Mississippian period Washausen mound center located in the American Bottom region of west-central Illinois. Population estimates are calculated based on data for residential architecture collected in 2011 during an extensive geophysical survey and excavations at the site. A magnetometer survey was conducted over 8 ha and produced a relatively complete site map revealing numerous household clusters organized around a central, earthen mound-and-plaza complex. Population estimates and site spatial information for Washausen are compared with similar data for earlier village communities located nearby, as well as other global village sequences, producing a demographic profile demonstrating a pattern of village growth and decline in the area after the onset of sedentism and agricultural intensification. Information from the region and elsewhere suggests that the development of larger communities through time resulted in part through frequent population movements as village seg- ments fissioned and aggregated to form new communities. This research finding has the potential to inform models for the growth of much larger American Bottom centers such as Pulcher and Cahokia. El crecimiento y la disminución de grandes pueblos es un tópico de interés para los arqueólogos estudiando el desarrollo de complejos gobiernos regionales. En este articulo presentamos información demográfica del centro montifico Washuasen durante el periodo transicional “Mississipian,” localizada en la región “America Bottom” en centro-oeste Illinois. Calculamos estimados de población basados en el data de arquitectura residencial que colectamos en el 2011 durante una extensiva inves- tigación geofisica y excavaciones en ese sitio. Conductamos una investigación magnometrica sobre ocho hectáreas y producimos un mapa detallando varios grupos de hogares organizados al rededor de un complejo montifico-y-plaza. Tambien comparamos estimados de población e información sitio-espacial de Washuasen con pueblos similares y cercanos de temporadas anteriores y también con comunidades globales. Producimos una descripción demográfica que demuestra un modelo de crecimiento y disminución en el área después del comienzo de sedentarismo e intensificación agricultural. Información de la región y otras localidades sugieren que el desarrollo de comunidades más grandes es debido al movimiento frecuente de poblaciones en forma de pueblos segmentados y fisionados que se agregan a nuevas comunidades. Los encuentros de este sitio tiene el potencial de informar modelos de crecimiento a centros más grandes del “American Bottom” como Pulcher y Cahokia. Casey R. Barrier  Department of Anthropology, Bryn Mawr College, Bryn Mawr, PA 19010 (cbarrier@brynmawr.edu) Timothy J. Horsley  Department of Anthropology, Northern Illinois University, De Kalb, IL 60115; Horsley Archaeological Prospection, LLC (timhorsley@gmail.com) American Antiquity 79(2), 2014, pp. 295–313 Copyright © 2014 by the Society for American Archaeology 295 Delivered by http://saa.metapress.com Society for American Archaeology - American Antiquity access (392-89-746) IP Address: 141.213.177.244 Tuesday, April 29, 2014 3:08:09 PM