1970s, are located on the western edge of the wilderness near Cougar Reservoir. See also List of Oregon Wildernesses List of U.S. Wilderness Areas Wilderness Act References External links Three Sisters Wilderness - Willamette National Forest Three Sisters Wilderness - Deschutes National Forest Wilderness.net Wilderness information TopoQuest map of the Three Sisters Former biosphere reserves of the United States Protected areas of Deschutes County, Oregon IUCN Category Ib Protected areas of Lane County, Oregon Wilderness areas of Oregon Willamette National Forest Deschutes National Forest 1964 establishments in Oregon Protected areas established in 1964