2023 Map of Grassy Ridge

About this map

The South Fork Owyhee Wild and Scenic River carves a deep canyon through this high-desert landscape in southwestern Idaho. This protected corridor is part of the extensive Owyhee River Wilderness, an area characterized by dramatic elevation shifts and volcanic plateaus. The topography is dominated by Grassy Ridge, which separates the river valley from the expansive Y P Desert to the east. Sparse water resources are captured in several small catchments, including Shea Reservoir, Coyote Flat Reservoir, and Coyote Hole Reservoir. The map illustrates the specialized hydrology required for life in Coyote Flat, where human-made reservoirs contrast with the natural drainage of the deep river basin. This recent survey from the U.S. Geological Survey documents the current state of these wilderness boundaries and the seasonal water sources critical to this arid environment.