Archaeological sites in beach and estuarine environments are continually threatened by diverse natural marine processes. Shoreline erosion, bluff retreat, and sea level rise all present potential for site destruction. Using historic maps, aerial imagery, and field survey methods in a GIS, 21 potentially significant archaeological sites on Georgia barrier islands were selected for determination of site-specific rates of shoreline change using a powerful, new, moving-boundary GIS analysis tool. A prioritized list of sites, based on the order of site loss from erosion, was generated to assist coastal managers in identifying and documenting sites most at risk. From the original selection of 21 sites, 11 sites were eroding, 8 shorelines were stable, and 2 shorelines were accreting. The methodology outlined here produces critical information on archaeological site loss rates and provides a straightforward means of prioritizing sites for detailed documentation