Congaree Swamp, the focus of the national park, is the largest area of virgin Southern bottomland hardwoods remaining in the United States. The park consists of an alluvial floodplain on the meandering Congaree River. Flooding occurs about 10 times a year but lasts only from several days to a month at a time, and for most of the year the area is dry. The tract includes loblolly pine, sweet gum, water tupelo, bald cypress, hickory, and oak—some of record size—and also rare and endangered species of both plants and animals, such as the red-cockaded woodpecker. Deer, opossums, foxes, feral swine, and bobcats are found in the swamp forest. Access to the park is by trail or boat; canoeing is a popular activity.