The Middle Santiam Wilderness protects an upper Middle Santiam landscape in Oregon’s central Cascade Range within the Willamette National Forest, near Mount Washington. Its terrain shifts from gentler bench-like lower lands and river valleys to steep slopes, ridgelines, and peaks at higher elevations. Notable features include Donaca Lake, the Middle Santiam River, and Chimney Peak, a 4,965-foot lava plug in the northwest; the Menagerie Wilderness lies just south. Much of the area is covered in mature old-growth forest, including stands about 450 years old and roughly 200 feet tall. It also preserves native fish habitat, with Chinook salmon present during spawning season.