The Oahe Dam and its two hundred-mile lake will cover many historic sites along the Missouri River. Oahe, a Dacotah (Sioux) word meaning "Something to stand upon," gave its name to a mission that Thomas L. Riggs, a Congregational missionary, established nine miles upstream in 1875. The large bottomland upstream on the east was known as Peoria Bottom after the Peoria Belle, a supply steamer for General Alfred Sully's troops, who camped there in 1863 while enroute to fight the hostile Santee Sioux farther north. In 1855-56, when General W. S. Harney came to Fort Pierre Choteau across the river, his prefabricated barracks were too flimsy, and the bottom, then unnamed, served as an ideal winter campsite that supplied logs for crude huts where many of his troops wintered. In 1867, Harney selected a new agency site about nine miles upriver, and many of its buildings were later used by Christian Indians, including Yellow Hawk (Cetangi), Spotted Bear (Mato-Gleska), and several others who took homesteads in the bottom. In the 14th century this area was the abiding place of an Indian culture that predated the Aricara, and in the 17th and 18th centuries it was the site of about twenty Indian villages and a large moated and palisaded fortress eleven miles upstream. It was also the site of the "Big Hut," an Indian gathering place for ceremonials called by the Dacotah Ti-tanka-ohe. Along this historic highway were numerous steamboat wrecks and sites including forts, agencies, missions, ranches, trade posts, monuments, villages, and ancient Indian fortifications.