The Castle can be visited
Herzberg Castle

In Breitenbach am Herzberg in the Hersfeld-Rotenburg district, Hesse, Germany, Herzberg Castle, a hilltop castle, stands at an elevation of approximately 500 meters above sea level. It is considered the largest hilltop castle in Hesse and is a testament to medieval defensive architecture.
History+
The construction of Herzberg Castle began between 1280 and 1290 under Heinrich von Romrod, marshal to Landgrave Heinrich I of Hesse. He had previously received five surrounding villages as a fief. The castle was likely completed around 1298, when Heinrich transferred it as a fief to the Landgrave. After the male line of the Romrod family died out in 1344, the castle passed into the possession of Berthold von Lißberg. His son Friedrich von Lißberg joined the Sternerbund around 1370, an alliance against the Hessian landgraves.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: Joachim Schneeleopard
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 50.7700, 9.4594