In connection with the development of the central Black Forest by the Benedictine monastery of St. Georgen, the Alt-Hornberg Castle, built by Adalbert von Ellerbach, once stood on the lower castle rock in Gremmelsbach, district of Triberg.

A two-meter-deep water cistern, beds for beams, wall base and rubble heaps are the only remains of the ancestral seat of the Lords of Hornberg and Triberg.

The access via the adventurous step system is already interesting. Once at the top of the rock, nature enthusiasts can enjoy a breathtaking panoramic view of the Gutach valley, in the north over the town of Hornberg to the Brandenkopf in the south, up to over 1.000 meters above sea level lying Black Forest heights around Triberg.

Fantastic views of the Middle Black Forest are also offered from the neighboring Oberer Schlossfelsen and from the Rappenfelsen.