A geomorphic investigation of Terrebone Marsh in south-central Louisiana was conducted to establish a framework for subsequent cultural resource investigations. The investigation consisted of an initial phase of detailed geomorphic mapping, subsequent field investigations, sedimentological, biostratigraphical, and chronological analyses of field samples, and palaeoenvironmental reconstruction of the area. The investigation substantiated and refined previous interpretations of the progradation of three Mississippi River deltas through the area. The earliest known Holocene delta, the Maringouin, was probably active in the area from 7000 to 6000 years. The Teche delta prograded through the area from 4500 to 3500 BP. From approximately 2000 to 1000 BP the LaFourche delta partially buried the Teche delta. The periods of approximately 6000-4500, 3500-2000, and 1000 BP to present were characterized by deltaic subsidence and erosion. Distributary natural levees and beach ridges appear to be sites of major cultural focus in Terrebonne Marsh. Due to high rates of subsidence, older cultural components are either buried or disturbed by erosion.