Mount Baker Wilderness in northern Washington, USA, contains 117,528 acres (475.62 km2). Its eastern border is shared with the boundary of the North Cascades National Park for a distance of 40 miles (65 kilometers). The Wilderness extends from State Route 20 north to the Canadian border. On the west, it is bounded by the foothills of the Puget Sound lowlands.
Almost entirely within Whatcom County, the wilderness lies on the western slopes of the Cascade Mountains. The three Forks of the Nooksack River and the Baker River are the major drainages of the wilderness.
Vegetative cover is typical of the west slopes of the Cascades including Western Redcedar, Coast Douglas-fir, Noble Fir, Pacific Silver Fir, Subalpine Fir, Western Hemlock and Mountain Hemlock, and at higher elevations, alpine meadows. Animals include Mountain Goats and Hoary Marmots. On mountains and higher ridges, considerable areas of rock and permanent glaciers (over 10,000 acres (40 km2)) occur.