Sawtooth Lake is an alpine lake in Custer County, Idaho, United States, located high in the Sawtooth Mountains in the Sawtooth National Recreation Area. The lake is approximately 6.8 mi southwest of Stanley. A trail from the Iron Creek trailhead and campground leads approximately 5 miles to Sawtooth Lake. The Iron Creek trailhead can be accessed from State Highway 21 via Sawtooth National Forest road 619. With a surface elevation of 8435 ft above sea level, Sawtooth Lake often remains frozen into early summer. At the southern end of the lake is Mount Regan at 10190 ft in elevation. Sawtooth Lake is in the Sawtooth Wilderness and wilderness permit can be obtained at trailheads. The hike to Sawtooth Lake from the Iron Creek trailhead is one of the most popular hikes in the Sawtooth National Recreation Area. This trail gains 1710 ft, takes 5 to 6 hours round trip, and offers great views of Alpine Lake, Alpine Peak, and the Sawtooth Valley. Visitors are permitted to camp anywhere in the National Forest, and Sawtooth Lake often serves as a camp for further hikes throughout the northern Sawtooth Wilderness.