Burg Kienburg, Castle ruin in Kienburg, Matrei in Osttirol, Austria

Burg Kienburg is a castle ruin situated on a steep rocky hill overlooking the Iseltal valley in Osttirol. The site contains irregular stone walls, a southern courtyard enclosed by a ring wall, and a residential section on the northern side built into the rock face.

First mentioned around the year 1000 and owned by the Counts of Lechsgemünd, the castle passed to the Archbishopric of Salzburg in 1212. In the mid-13th century Archbishop Philipp von Spanheim seized imperial castles, prompting Count Meinhard III of Görz to raid Matrei and Virgen; the 1252 Peace of Lieserhofen settled the conflict, but Kienburg remained contested. A fire in 1579 made it uninhabitable, and the last knight, Count Christoph von Kienburg, abandoned it.

The name Kienburg comes from the Old German word kühn, meaning bold or daring. The castle gave its name to the hamlet of Kienburg between Huben and Sankt Johann im Walde. Today the ruin stands on private land where the Stocker family runs forestry and a hay bath (Heubad) wellness facility.

The location sits on a steep hill, so sturdy footwear and some stamina are needed for the climb. Access is via forest paths, and caution is advised during rain as the trails can become slippery.

The castle was struck by an American bomb during World War Two, causing massive damage to the main buildings and tower. Parts of the bomb's metal casing remain visible today, serving as a reminder of this unexpected wartime impact.