Underlying all archaeological investigations in riverine environments, there needs to be as full an understanding as possible of the history of the fluvial system in question because fluvial history influences taphonomy and archaeology. Detailed investigation of five sites on the Holocene floodplain of the Exe River, southwest England, has extended our knowledge of channel change and fluvial sedimentation in this area. New dating from optically stimulated luminescence (OSL) has been combined with previous radiocarbon dates from the Upper and Lower Exe, and the resulting chronology is in approximate agreement with the phases of fluvial change described from southern Britain that appear to relate to Holocene climate shifts. Over the mid–late Holocene, avulsion and reoccupation of former channels have occurred, while in historic time, channel systems have been relatively stable, with some oscillation around channel bars or islands. The recognition of this change in channel behavior in the very late Holocene at a classic site has solved what had been a “floodplain paradox”—a contradiction between the rates of historical channel lateral migration and archaeology found on, and in, UK floodplains. The reoccupation of former channels allows lateral deposits to be stacked and is part of floodplain aggradation by overbank and bed sedimentation. This has significant implications for the preservation of archaeological material, including artifacts. Mesolithic artifacts have been found on the valley floors within the Exe catchment; their preservation has, to a large extent, been controlled by the style of Late Glacial and Holocene floodplain development.