The Mummelsee is a 17-metre-deep lake at the western mountainside of the Hornisgrinde in the Northern Black Forest of Germany. It is very popular with tourists travelling along the Schwarzwaldhochstraße. According to legends, the lake is inhabited by a Nix and the King of the Mummelsee.
The Mummelsee has a circumference of approximately 800 m (2,625 ft) and is surrounded by steep and forested mountain slopes on its northern, western and eastern sides. The western lakeside rises towards the mountain "Katzenkopf" (1,123 m (3,684 ft) above sea level) and the northern lakeshore rises towards Hornisgrinde. With 1,163 m (3,816 ft) above sea level, Hornisgrinde is the highest mountain in the Northern Black Forest. Solely the southern lake banks are (nearly) flat. This also being the place where the alpine hotel "Mummelsee" and the close-by St. Michaels chapel are located.
See Bædeker The Rhine from Rotterdam to Constance (1878) Route 47 page 298