Burg Klingenstein, Medieval castle in Blaustein, Germany

Burg Klingenstein is a castle in Blaustein whose structure features massive stone walls and towers typical of medieval defensive fortifications. The buildings show the spatial layout of a fortified stronghold with multiple levels and defensive positions.

Burg Klingenstein was built from the 11th century by the Lords of Stain zu Klingenstein and first mentioned in 1215. It was abandoned after 1588. The complex originally consisted of three castles: the Upper Castle with keep, chapel and drawbridge, the Middle Castle with gatehouse and shell tower, and the Lower Castle, on whose foundations Schloss Klingenstein now stands.

The name Klingenstein comes from the Lords of Stain zu Klingenstein, who built the castle from the 11th century and were mentioned in 1215. The site is now owned by the Leube-Stiftung, a foundation under civil law that has maintained the ruin and neighbouring Schloss Klingenstein since 1974. The ruin can normally be visited only on official occasions such as the Tag des offenen Denkmals.

The castle can be viewed from the outside and offers vantage points over the surrounding countryside. It is advisable to wear comfortable shoes as the terrain is uneven and access to some areas can be difficult depending on the season.

The ruin is split into three separate castles: the Oberburg, Mittelburg and Unterburg. Only the keep's foundations survive from the 11th–12th-century Oberburg, while the Mittelburg's shell tower still stands. The Unterburg's cellars now support Schloss Klingenstein, built on its walls.