South Warner Wilderness is a federally protected wilderness in the Warner Mountains of northeastern California, encompassing more than 70,000 acres in Modoc National Forest. First protected in 1931 as a primitive area, it became wilderness in 1964, with additional acreage added in 1984. Rising from about 5,000 feet to 9,895 feet at Eagle Peak, it includes a narrow crest dividing waters that flow west toward the Sacramento and Pit River drainage from those that run east into Surprise Valley. Its fault-block, volcanic landscape holds lakes, streams, forests, rare plants, and varied wildlife, while extensive trails support hiking, fishing, horseback riding, and winter travel.