Fish populations include brook and rainbow trout. There are approximately 260 miles of trail within the wilderness. The Pacific Crest National Scenic Trail traverses the wilderness for 40 miles. Most trails entering the wilderness begin in dense forests of Douglas-fir on the western slopes of the Cascades and ponderosa pine on the eastern slopes. Alpine meadows are abundant.
Many trailheads access the wilderness.
Green Lakes, Obsidian, Sunshine, Erma Bell Lakes, South Sister Climbing Trail. Recreational use in Three Sisters Wilderness is the highest of all wildernesses in the Willamette National Forest. Use has doubled from 1982 to 1992. Day and overnight visitors entering the wilderness are required to obtain a permit between Memorial Day and October 31. They are free of charge and must be self-issued at trailheads.