Sylvan Lake, known as the "crown jewel" of Custer State Park, is located in the Black Hills of South Dakota. Created in 1881 when Theodore Reder built a dam across Sunday Gulch, it offers picnic areas, rock climbing, small rental boats, swimming, and hiking trails.
It is also popular as a starting point for excursions to Harney Peak and The Needles. From the top of Harnes Peak...