Across the canal, the Great Dismal Swamp National Wildlife Refuge preserves the heart of a once vast, biologically rich wetland that covered as much as one million acres of southeastern Virginia and northeastern North Carolina, stretching from the Suffolk scarp to the Albemarle Sound and from Deep Creek in Chesapeake to Edenton, North Carolina. Established in 1974 by an Act of Congress, the refuge now protects over 112,000 acres. The swamp served not only as a refuge for wildlife but also for people, harboring generations of freedom seekers within its dense wetland forest as hundreds or even thousands of runaway slaves traveling from south to north moved through its dark waterways; some remained there, while others continued to Norfolk and Portsmouth with help from the web of assistance that became known as the Underground Network. Today, the refuge and the Dismal Swamp Canal are official sites in the National Park Service's Underground Railroad Network to Freedom. The refuge is one of more than 550 refuges in the National Wildlife Refuge System, managed by the U.S. Fish and Wildlife Service, and formal protection of this resource began in 1973 when the Union Camp Corporation donated 49,097 acres to The Nature Conservancy.