Unterwildenstein Castle (Ruin)

Unterwildenstein Castle is a high medieval castle ruin of free noble affiliation north of the municipality of Leibertingen in the district of Sigmaringen in Baden-Württemberg, Germany. It is one of four castles that were built long before Wildenstein Castle.

The ruin of the rock castle is located northeast of the Altwildenstein ruin, not far from the so-called "Ritterweg" (Knight's Path), on an isolated rock ridge at 730 meters above sea level on a valley slope. The rock has a gully in the southwest and drops steeply to the northeast side.

Unterwildenstein, presumably dating from the 12th century, cannot be clearly identified as an independent complex or as belonging to the Altwildenstein Castle located above it, as there are no documents to this effect. Only wall remains indicate the ruin located on a rock ridge, which features the peculiarity of a cave extending approximately 10 m into the castle rock.

From Unterwildenstein, wall remains have been preserved on the valley side of the rock. A rock gully in front of the castle site was walled up.