The Shasta-Trinity National Forest is a federally designated forest in northern California, United States. It is the largest National Forest in California and is managed by the U.S. Forest Service. The 3,454-square-mile (8,945.5-square-kilometer) forest encompasses five wilderness areas, hundreds of mountain lakes and 6,278 miles (10,103 km) of streams and rivers. Major features include Shasta Lake, the largest man-made lake in California and Mount Shasta, elevation 14,179 feet (4,322 m). The Shasta-Trinity National Forest offers a wide range of recreational activities. Some of these include hiking, backpacking, mountain climbing, horseback riding, camping, boating, fishing, hunting, sightseeing, downhill skiing and riding, snowboarding, cross-country skiing, and snowmobiling. In descending order of land area, the forests are located in parts of Trinity, Shasta, Siskiyou, Tehama, Modoc and Humboldt counties.