Burg Marsbach, Medieval fortress in Hofkirchen im Mühlkreis, Austria

Burg Marsbach is a medieval fortress perched on a narrow terrace above the Danube River. The structure comprises a three-story rectangular main building with a round tower and southern extension that give the complex its cohesive form.

The 1075 mention of "Raffoldus de Morspah" is a forgery; the Marsbacher, ministerials of Passau, descend from Wernhard von Wesen, named after Marsbach around 1170. In 1248 King Henry VII outlawed Henry von Marsbach, who surrendered the castle to the Bishop of Passau; in 1267 Otto and Ortolf II seized it from their father Ortolf I. After feuds, Marsbach returned to Passau in 1281 and stayed with the bishops until secularisation in 1803.

The castle was the seat of the Passau bishopric's district court from 1529, when the court previously held at Velden (today Neufelden) was moved here. Bishops appointed chief stewards such as Veit Tattenbeck (1591–1624) to govern the Mühlviertel from Marsbach. In 1594, during the Turkish wars, the population used it as a refuge castle.

The fortress is privately owned and requires advance permission for visits, which means planning ahead is necessary. The location is accessible by public transportation from the nearby town of Hofkirchen im Mühlkreis.

The castle stands on a steep drop on the left bank of the Danube, and its ridge position allowed the lords to watch the river from Niederranna to the Schlögener Schlinge. In 1594, during the Turkish wars, the fortress served as a refuge for the local population. The square keep at the eastern end survives from the 13th-century castle; the rest was rebuilt after 1561.