The federal Wilderness Act was signed into law by President Lyndon B. Johnson on Sept. 3, 1964.
Back then, 9.1 million acres making up 54 wilderness areas in 13 states were designated as wilderness. Since then, the national wilderness system has grown to include 758 designated wilderness areas covering more than 109 million acres of land, including 3.4 million in Montana.
John Gatchell of the Montana Wilderness Association says Montanans played a key leadership role in the passage of the Wilderness Act.
Gatchell tells the Great Falls Tribune that the concept of wilderness was pioneered by Bob Marshall, for whom Montana's Bob Marshall Wilderness is named.
The last wilderness designation in Montana was in 1983.
And wilderness advocates say more land in the state could be designated for protection.