Range size and dynamics of black bears (Ursus americanus) were determined in Great Dismal Swamp (GDS), an 850-km2 forested wetland straddling the eastern border of Virginia and North Carolina. Male ranges were larger (P < 0.05) than female ranges annually and seasonally. Median range sizes were 21.4 km2 for adult females (N = 11),33.1 km2 for subadult females (N = 7), and 79.0 km2 for males (N = 10). Extensive fall movements inflated female ranges. Range shifts were maximal from late summer to early fall and early fall to late fall, averaging 4.4 ± 0.7 km (N = 14) and 4.4 ± 0.8 km (N = 17), respectively. Annual and seasonal overlap were extensive within and between sexes, with female range overlap increasing from spring to early fall. Range use and territoriality among female bears were influenced by spatial and temporal distribution of food.