Common land
The Idaho Batholith underlies most of Boise National Forest, forming the forest's Boise, Salmon River, and West mountain ranges; the forest reaches a maximum elevation of on Steel Mountain. Common land cover includes sagebrush steppe and spruce-fir forests; there are of streams and rivers and of lakes and reservoirs. Boise National Forest contains 75 percent of the known populations of Sacajawea's bitterroot, a flowering plant endemic to Idaho.