Most towns were crucial to the initial colonization and economic development of the Great Plains. Many were, directly or indirectly, creatures of railroad corporate planning, owing their location as well as their physical layout to the townsite companies controlled by railroad officials. This article examines how these facts shaped the fundamental long-term look of urban South Dakota, and by extension that of the Great Plains, and how later, even with the railroads' regression and the shift to the modern highway, that history remains embedded in contemporary townscapes. But the image is not a single one--there are at least six different urban South Dakotas set within the state's varied geography, each of which will be briefly characterized. (Contains 6 notes, 1 table, and 13 figures.)