Geyersburg, Castle ruin in Untermünkheim, Germany.

Geyersburg is a ruined spur castle on a narrow ridge above the Kocher valley near Untermünkheim. Its partly preserved three-story residential tower has an octagonal plan, walls of Muschelkalk limestone about 1.5 meters thick, and a cellar reached by a stone staircase. The outer wall shows slit openings, while the upper floor has large rectangular windows with seating niches. Section ditches and a shield wall also belonged to the complex.

The Feldner family, part of the Hall patriciate, built the castle in 1391. In 1402 Hans Feldner, called Geyer, is documented in connection with the fief. The castle passed to the city of Hall, which sold it in 1406 to Rudolf von Münkheim; after the Münkheim family died out in 1507 it lost importance.

The name Gartenheuslin, recorded in the 16th century, points to the site's later use as a garden house rather than a lordly residence. In the 1520s a group of peasants occupied the fortress during the German Peasants' War. The ruin was consolidated in 1982 and has been freely accessible since.

The site sits at 320 meters above sea level and can be reached from the nearby community of Sülz about one kilometer to the southwest. The approach is fairly short and takes you through the surrounding landscape.

The ruin was restored in 1982 and has been freely accessible since. Its name recalls Hans Feldner, called Geyer, who is documented in 1402 in connection with Ulrich von Hohenlohe and the fief of the Geyersburg.