Covering 3.36 million acres (13,600 km2), the forest is broken into nine separate sections and stretches across eight counties in the southwestern area of the state.

He created this reserve because the Anaconda Copper Mining Company, based in Butte, Montana, had begun to clearcut the upper Big Hole River watershed.

Lemhi Pass, at an elevation 7,323 feet (2,232 m) above sea level, is a rounded saddle in the Beaverhead Mountains of the Bitterroot Range, along the Continental Divide, between Montana and Idaho.

Here, in 1805, the Lewis and Clark Expedition first saw the headwaters of the Columbia River, which flow to the Pacific Ocean, and crossed what was then the western boundary of the United States.

Lemhi Pass was the point at which the members of the expedition realized that there was not a waterway that would lead from east to west across the continent.

The Lee Metcalf Wilderness, in the Madison mountain range, is a part of what is known as the Greater Yellowstone Ecosystem.

Elk, mule deer, moose, bighorn sheep, pronghorn, coyote, and black bear are more commonly seen.