Compared to reservoirs and small impoundments, sport fisheries management infrequently has been attempted in large-river systems. In river systems of the southeastern United States, black crappie (Pomoxis nigromaculatus) and white crappie (P. annularis) represent popular sport fisheries in floodplain lakes and other off-channel habitats. Using floodplain lakes in the lower White River, Arkansas as a study area, crappie population data from 16 representative lakes were used to define basic stock structure statistics and evaluate whether minimum-length limits could potentially improve crappie fisheries in this system. Modeling indicated that implementation of a 254-mm minimum-length limit for crappies would reduce the number of fish harvested by half and minimally increase yield when exploitation was high. Modeling also suggested the length limit would increase mean size (length and weight) harvested, with more substantial increases observed when recruitment was held constant. In the presence of high recruitment variability (incoming number of recruits CV >75%), length-limit implementation exhibited similar trends with yield and harvest as with low recruitment variability (incoming number of recruits CV <50%), and produced minimal improvement in population size structure. However, within this modeling scenario, greater variability was observed in all predicted population statistics over long-term time scales, which suggested that years of high-quality crappie fisheries would be balanced with as many poor years. Modeling suggested that minimum-length limits provided minimal benefits for crappie fisheries in lower White River floodplain lakes. These findings were generally similar to previous studies on these species done in reservoirs and small impoundments.