Fishing and swimming are also popular activities at some of the more accessible areas of the river. This unit encompasses the 12 mile length of the canyon, including the canyon rim but not the river and its associated floodplain. The canyon is one of the longest and deepest in the eastern United States, dropping at times more than 500-600 feet from the bluffs down to the river. Dominated by cliff and gorge walls cut into the sandstone, limestone and shale rocks, this unit has a biological component influenced strongly by the steepness of the slopes. The vegetation is mostly second growth trees with a mix of hardwoods and pine, and natural succession is evident in areas where hardwood forests are gradually replacing the pines.
Soils are generally very shallow along the cliffs and outcrops.
With the exception of Little River and its floodplain, this unit comprises most of the Preserve from the vicinity of Highway 35 northward. Topographically, the area is mostly gently sloping, with most of the variation in elevation associated with drainage slopes towards Little River. Given the high quality of the system and the presence of natural ecosystem processes, Little River is believed to exhibit an exceptional degree of biological integrity. This conclusion is supported by the documented presence of several federally listed species within the Preserve. The U.S. Fish and Wildlife Service lists seven other threatened or endangered species as possibly occurring within the Preserve.