The basin, which is susceptible to long periods of deep flooding, is sparsely inhabited. The Basin is about in width from east to west and in length. The Basin is the largest existing wetland in the United States with an area of , including the surrounding swamps outside of the levees that historically were connected to the Basin. The Basin contains nationally significant expanses of bottomland hardwoods, swamplands, bayous, and back-water lakes. The Basin's thousands of acres of forest and farmland are home to the Louisiana black bear "(Ursus americanus luteolus)," which has been on the United States Fish and Wildlife Service threatened list since 1992.