1989 Map of East of May

About this map

The Pahsimeroi Valley occupies the heart of this landscape, where the wide alluvial floor is defined by the braided path of the Pahsimeroi River. This 1989 provisional survey captures the transition from the high eastern peaks of the Challis National Forest to the productive ranching and agricultural flats of Lemhi County. The drainage pattern is the dominant organizational force here, with numerous watercourses like Morse Creek, Patterson Creek, and Falls Creek descending from the mountain front to join the primary river system. Evidence of local land use is sparse but specific, noted by a Borrow Pit and the boundary line between Lemhi Co and Custer Co. The map reveals a specialized high-desert mountain environment where water management and topographical boundaries dictated the placement of early routes and resource extraction sites.