Magnetometry and conductivity surveys were conducted on Groves Creek Site (09CH71), Skidaway Island, Georgia in order to detect subsurface archaeological features. The data from these surveys were processed in a geographic information system (GIS) to evaluate GIS as a geophysical processing tool for archaeologists. While the GIS constructed for this project was found to be adequate, a system with analytical capabilities more suited to geophysical data would have been preferable. Several anomalies detected by the geophysical surveys were excavated, and one proved to be an Irene phase (AD 1300-1450) structure (Structure 5). Data gathered from the excavation of Structure 5 coupled with data from four structures previously excavated at the site, structures from other sites, and ethnohistoric accounts from early European chroniclers were compared in order to characterize Irene phase architecture on the Georgia coast. The majority of archaeological structures were square or rectangular and constructed of wattle and daub; however, they varied in size and several aspects of construction. The ethnohistoric accounts indicate that the majority of structures were round and built using a variety of construction techniques. The difference in shape between archaeological and ethnohistoric accounts may be the consequence of social changes following European contact or change over time. Data from Structure 5 and a midden unit were used to determine the subsistence strategies and season of occupation of Groves Creek Site. Faunal, botanical, Boonea impressa (an oyster parasite) measurement data and stable isotope analysis of oyster shells were used to determine that the site was occupied year round, and that crops provided a significant component of the diet. A revised model of coastal subsistence strategies is proposed, in which the late prehistoric inhabitants of the coastal plain resided in dispersed, sedentary hamlets and relied on a mix of agriculture, gathering wild plants, fishing and hunting.