1966 Map of Mahto NE

About this map

Oahe Reservoir dominates the eastern edge of this 1960s landscape, marking the flooded valley of the Missouri River along the state border between North Dakota and South Dakota. The sheet illustrates a complex intersection of administrative lines, where the Standing Rock Indian Reservation Boundary meets the borders of Sioux, Emmons, Campbell, and Corson counties. The terrain is defined by a network of drainage systems feeding the reservoir, including the winding paths of Fireheart Creek and Joe Bush Creek in the north, and Blackfoot Creek and Hunkpapa Cr to the south. State Line Bay provides a clear landmark where the rising waters of the reservoir crossed the state boundary. Significant elevation features such as Baldhead overlook the rugged breaks that lead down to the water’s edge, revealing the topography of the region before further modern development.