2015 Map of Twentyone Divide

About this map

Twentyone Divide serves as the dominant landform in this high-plains landscape where the Wyoming and South Dakota borders meet. This 2015 survey illuminates the transition from the protected timber of the Black Hills Nat For in the northeast down into the expansive open range of the Buffalo Gap National Grassland to the south. The arid geography is defined by drainage patterns like Twentyone Draw and the course of the Cheyenne River, which cuts across the lower half of the quadrangle. Sparse infrastructure, including Dewey Rd and Argentine Rd, suggests a remote ranching economy dependent on water features such as Williams Reservoir. This map is particularly valuable for documenting the modern intersection of Niobrara, Custer, and Fall River counties along the interstate line.