Custer National Forest is located primarily in the south central part of the U.S. state of Montana but also has separate sections in northwestern South Dakota. With a total area of 1,188,130 acres (4,808 km2), the forest comprises over 10 separate sections. While in the westernmost sections, Custer National Forest is a part of the Greater Yellowstone Ecosystem, the easternmost sections are a combination of forest "islands" and grasslands. A portion of the forest is also part of the Absaroka-Beartooth Wilderness and constitutes over a third of the wilderness land. South of Red Lodge, Montana, the Beartooth Highway (U.S. 212) passes through the forest en route to Yellowstone National Park.
The eastern areas are dominated by large stands of ponderosa pine surrounded by grasslands, which are often leased to local ranchers for cattle grazing.
The western sections have a mixture of pine, spruce and fir trees due to the increased altitude and more abundant rainfall. Higher altitudes deep into the wilderness areas are above timberline and alpine conditions prevail. The tallest mountain in Montana, Granite Peak, is shared with Gallatin National Forest, as is the interesting Grasshopper Glacier, which has millions of grasshoppers that died approximately 300 years ago, entombed within the ice.
There are over 30 vehicle accessible campgrounds in the forest, as well as numerous picnic areas. Over 1,500 miles (2,400 km) of hiking trails are available with most being found in the western district. Though not plentiful with rivers and lakes, the waterways do provide some opportunities for fishing but little for boating. The forest headquarters is located in Billings, Montana, and most hiking and camping is done in the region south and southwest of Billings. There are local ranger district offices in Ashland and Red Lodge in Montana, and in Camp Crook in South Dakota.[4]
