The Story
Sylvan Lake was created in 1891 when Theodore Reder dammed Sunday Gulch Creek to draw early Black Hills tourists — nearly thirty years before Custer State Park was established in 1919. The lake wasn't absorbed into the park until 1921. Ringed by wind-sculpted granite domes at the west end of the Needles Highway, it got a national spotlight in 2007 when "National Treasure: Book of Secrets" digitally positioned it right behind Mount Rushmore — a Hollywood geography trick, since the real lake is about five miles southwest.
Surprising Facts
→ The lake is man-made — formed by an 1891 dam built to boost early tourism.
→ It existed for 28 years before Custer State Park was created, and wasn't added until 1921.
→ "National Treasure 2" places it right behind Mount Rushmore; in reality it's five miles away.