2017 Map of Sourdough Flats

About this map

The Belle Fourche River meanders through this Butte County landscape, cutting a path through the expansive prairie terrain of Sourdough Flats and Windy Flats. This 2017 survey by the U.S. Geological Survey captures a region defined by its drainage systems, where Middle Cr, Crow Cr, and Grummit Canyon Cr feed into the primary river valley. South of the flats, the terrain descends into the prominent Big Canyon, which is flanked by a network of rural roads including Canyon Creek Dr and Bonato Rd. The grid of the Public Land Survey System is evident here, with township lines like t9n r1e and t8n r2e organizing the cattle-and-river country. The density of road labels such as Livestock Rd and Cattle Dr reflects the ongoing agricultural and ranching heritage of this South Dakota expanse.