Three Sisters Wilderness is a vast protected mountain landscape in Oregon’s Cascade Range spanning the Willamette and Deschutes National Forests. Established by Congress in 1964, it is Oregon’s second-largest wilderness area and takes its name from the Three Sisters volcanoes, with Broken Top also rising within its bounds. Its terrain ranges from low forest to the summit of South Sister, shaped by both volcanism and glaciation, including Oregon’s largest glacier, Collier Glacier. Forests, alpine meadows, and the headwaters of Whychus Creek support a landscape prized for hiking, camping, climbing, and fishing, with more than 260 miles of trails including part of the Pacific Crest Trail.