Long Pine National Forest was originally established as the Long Pine Forest Reserve in Montana on September 24, 1906 with 111,445 acres (451.00 km2).
It became a National Forest on March 4, 1907.
On July 1, 1908 it was absorbed by Sioux National Forest and the name was discontinued.
[1] The forest today comprises the Long Pines unit of the Sioux Ranger District of Custer National Forest, in Carter County, Montana with 320 acres in Harding County, South Dakota.
[2]