Burgruine Eibenstein, Medieval castle ruins in Raabs an der Thaya, Austria.

Burgruine Eibenstein is the ruin of a hilltop castle on the south bank of the Thaya, opposite the village of Eibenstein and its parish church of St. Giles. The surviving masonry includes stretches of the north wall, built on a steep rock face, and the foundations of a chapel.

Eibenstein was first documented in 1194. On 24 April 1543 the castle was sold to the brothers Christoph and Erasmus von Schneckenreith, whose family died out in 1569. At an unrecorded date it came under the lordship of Drosendorf and is still owned by the Hoyos family. During the Thirty Years' War the ruin was at least temporarily inhabited.

The ruins show how medieval residents built fortified homes and chapels on steep cliffs to guard river passages. The site reflects the way local nobility lived and controlled the surrounding lands from this commanding position.

The ruins can be visited throughout the year without charge and are reached via marked paths from the village of Eibenstein. The steep climb requires sturdy footwear and caution, especially in damp conditions.

A large section of the north wall collapsed into the Thaya River in 1867 and still lies on the riverbed. This collapse changed the ruins permanently and makes the water below an unexpected part of what visitors see.