Northern Plains National Heritage Area is a federally designated National Heritage Area along an 80-mile (130 km) length of the Missouri River in central North Dakota. The heritage area promotes and interprets the scenic, cultural and historic heritage of the region. It extends from Knife River Indian Villages National Historic Site to Huff Indian Village State Historic Site The area interprets the history of the Three Affiliated Tribes, the passage of the Lewis and Clark Expedition, the fur trade, steamboats on the Missouri and Fort Abraham Lincoln. It also interprets the area's association with the Northern Pacific Railroad, as well as the area's heritage in agriculture and energy production.