The Shasta–Trinity National Forests are federally designated forests in northern California, United States. Combined, they are the largest National Forest in California and are managed by the U.S. Forest Service. The 2,210,485 acre combined-forest encompasses five wilderness areas, hundreds of mountain lakes and 6,278 miles of streams and rivers. Major features include Shasta Lake, the largest man-made lake in California and Mount Shasta, elevation 14,179 feet.
The Shasta–Trinity National Forests offer 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.