Excavations at two Late Archaic shell rings on St. Catherines Island, Georgia, revealed evidence of significant amounts of subterranean storage. Based on botanical evidence, ethonographic analogies, and interpretations of other Late Archaic sites, hickory nuts and acorns are the most likely resource being stored, and quantifying the capacity found at each ring highlights the prevalence and importance of mast storage. These findings are important because large-scale storage has rarely been proposed for Late Archaic coastal peoples and, therefore, its impact as a potential factor for social changes enacted during this time period, including increasing sedentism, formalization of intragroup relations, and regionalization of cultural identities, has yet to be explored.