Traditional Narratives of the Arikara Indians, Volumes 3 & 4Until the late eighteenth century the Arikaras were one of the largest and most influential Indian groups on the northern plains. For centuries they have lived along the Missouri River, first in present South Dakota, later in what is now North Dakota. Today they share the Fort Berthold Indian Reservation in North Dakota with the Mandans and Hidatsas. Although their postcontact history and aspects of their culture are well documented, Douglas R.