Treis Castle, Medieval castle ruins in Treis-Karden, Germany

Treis Castle consists of ruins positioned on a mountain ridge in the Hunsruck region, set above river valleys and surrounded by dense forest. The square keep and portions of the defensive wall remain standing, offering views of the surrounding landscape and nearby streams.

The original structure fell to Emperor Henry V in 1121 when it belonged to Count Otto I of Salm. It was rebuilt under the control of the diocese of Trier and finally destroyed by French forces in 1689 during a regional succession conflict.

The castle's name comes from Treis, the village below; the free lords of Treis were among the Trier ministeriales who served as bailiffs there. In the 12th and 13th centuries the Archdeacon of Karden controlled the castle, and later the Lords of Pyrmont, Winneburg-Beilstein and Eltz held it as Trier fiefs.

Access to the ruin is closed (as of 20 August 2015), so the keep and curtain wall can only be viewed from outside. The site lies about one kilometre south of Treis, off the Moselle valley, on a spur above the confluence of the Flaumbach and Dünnbach. Wildburg Castle stands roughly 150 metres to the south on the same spur, separated by a hollow.

The keep was raised by one storey and given a roof during restoration, reinstating its original appearance. Access to the ruin was restricted as of 20 August 2015. In mid-2020 the municipality of Treis-Karden acquired both castles on the spur, Treis and Wildburg, intending to use them for cultural and tourism purposes.