The Idaho portion of Hells Canyon Wilderness is characterized by three geologic-vegetative regions. The upper areas are alpine and subalpine with several lakes and geologic formations of glacial origin. Vegetation is sparse and broken by large areas of rock. The middle portions contain dense forests of larch, lodgepole pine, and true firs. Lower elevations are characterized by dry, rocky, barren, steep slopes breaking into the Snake River and its major tributaries. Trees are sparse, consisting mostly of ponderosa pine and Douglas fir. This entire area is dissected by several major drainages including Sheep Creek, Granite Creek, and Deep Creek. The highest peaks are the Seven Devils Mountains, the tallest is He Devil at above sea level.