A separate section of the forest north of Livingston, Montana, is located in the Crazy Mountains which rise over 7,000 ft (2,100 m) above the Great Plains to the east.

The forest includes two wilderness areas, the Absaroka–Beartooth and the Lee Metcalf, along with some of the tributaries for the Yellowstone, Madison, and Missouri rivers.

Many western North American species are represented in this climax ecosystem including elk, mule deer, bison, moose, bighorn sheep, pronghorn, cougar, gray wolf and black bear.

[4] Various subspecies of trout are plentiful in the streams and they contribute to the forest being one of the preeminent fly fishing regions in the United States.

[3] There are seven local ranger district offices for the forest, with locations in West Yellowstone, Livingston, Bozeman, Gardiner, Ashland, and Red Lodge for Montana and Camp Crook for South Dakota.

Nighttime temperatures can be below freezing any time of the year, and mosquitoes in the late spring and early summer are abundant.