Burgstall Schlüsselstein, Archaeological site in Ebermannstadt, Germany.

Burgstall Schlüsselstein is a levelled castle site on a 150-metre-long rocky spur of the Kreuzberg at 489.6 m above sea level, jutting southwest into the Wiesent valley. It is divided into a main ward and an outer ward, separated by a curved neck ditch about 25 metres long and 1.7 metres deep. The outer ditch, 35 metres long and 13.5 metres wide, still shows a 1.5-metre stretch of dry stone walling.

The site was founded in the second half of the 12th century and represents an early fortification by the Schlüsselberg family. The construction with main and outer ward shows the strategic importance of controlling the valley below.

The name Schlüsselstein connects to the noble family of Schlüsselberg, who built this fortification during medieval times. Visitors walking through the site can still trace this historical naming link today.

The site is reached on foot via a hiking trail; the route crosses the outer neck ditch just before its southern end, where the original entrance probably lay. The summit of the spur, marked by a cross, is wooded and partly overgrown with bushes, and an information board stands in the outer ward.

The rectangular outer bailey shows no traces of buildings, suggesting it served mainly for defense rather than residence. This distinction between living and protective areas likely revealed the fortification's purpose hierarchy.