Using the concept of bone functional adaptation, this study analyzes femoral and humeral cross-sectional properties of human skeletal materials from Morton Shell Mound on the Louisiana coast. This work helps fill a gap in such analyses in the southern U.S. and contributes to an understanding of the functional adaptation of the human skeleton. Properties were compared to those of other prehistoric Southeastern fisher-hunter-gatherers from Gold Mine, Plash Island, and several Georgia coast sites to assess mobility and activity patterns among inland and coastal groups. Less sexual dimorphism of femoral midshaft shape among coastal Morton and Plash, compared to inland Gold Mine, indicates lower terrestrial logistic mobility. Greater robusticity (not significant) in coastal samples is linked to an expanded subpersiosteum, rather than terrestrial logistic mobility. Both coastal and inland samples exhibit round humeral shape, typical of fisher-hunter-gatherers.