The Coteau des Prairies: An Area Study

This thesis is a systematic geographical analysis of the Coteau des Prairies of eastern South Dakota. The Coteau is a flatironed-shaped plateau about 200 miles in length pointing in a northerly direction (Fig.1). The northern tip of the flatiron-shaped Coteau ends at Sargents Point, North Dakota, about 15 miles north of Marshall County, South Dakota. The heel of the flatiron or the southern edge of the Coteau des Prairies would just about follow the border between Minnehaha and Lincoln Counties of South Dakota. The eastern edge of the Coteau\u27s extent in South Dakota parallels the Minnesota border. In Deuel County, South Dakota it veers northwesterly and ends at Sargents Point, North Dakota. The western edge of the Coteau extends through Marshall, Day, Clark, Kingsbury, Miner, Lake, McCook, Minnehaha and northern Lincoln Counties. Like a flatiron, the Coteau widens and its vertical protrusion diminishes as it extends southward. Its maximum width is about 70 miles