In recent years, many geological studies have been conducted along the coastal embayments and nearshore areas of the Gulf of Mexico, including Tampa Bay, Mobile Bay, Lake Pontchartrain, Calcasieu Lake, Sabine Lake, Nueces Bay, and Corpus Christi Bay. Processes driven by sea-level change during the late Wisconsinan regression and subsequent Holocene transgression have formed the bays and estuaries of the Gulf of Mexico. Erosion by fluvial systems during the late Wisconsinan lowstand cut valleys across the continental shelf. The rapid Holocene transgression forced coastal-plain shorelines landward. As sea-level rise slowed, the incised valleys became estuarine depocenters. Estuarine sediments deposited in the alluvial valley during the initial flooding of the valleys overlie lowstand fluvial and interfluvial deposits. During the present highstand, wave reworking and longshore sediment transport formed shoals or barrier islands across the estuary mouths creating restricted estuaries into which bayhead deltas have prograded. Late Holocene deposition in the estuaries has been dominantly lagoonal sediments. A conceptual model incorporating these erosional and depositional processes with sea-level change has been developed. The model effectively describes the evolutionary succession from incised valley to estuary, exclusive of fluvial source or sediment supply.