Little Belt National Forest was established as the Little Belt Forest Reserve by the U.S. Forest Service in Montana on October 3, 1905 with 583,600 acres (2,362 km2) after a name change from Little Belt Mountains Forest Reserve, which was established on August 16, 1902 with 501,000 acres (2,030 km2). It became a National Forest on March 4, 1907. On July 1, 1908 the entire forest was combined with Highwood Mountains, Snowy Mountains and Little Rockies National Forests to establish Jefferson National Forest and the name was discontinued. The lands are included in Lewis and Clark National Forest.