2017 Map of Cowan Reservoir

The terrain is marked by dramatic geological formations, from the flat-topped Arch Table and Dorsey Table to the deep incision of Arch Canyon. In the southwest corner, the curious geological depression known as Hole in the Ground provides a distinctive landmark. Drainages like Cougar Cr and Dorsey Cr carve through the plateau, illustrating the natural watershed patterns that collectors and researchers use to understand historical land use and livestock movement in this part of Idaho.