Burgruine Haichenbach, Medieval castle ruin in Hofkirchen im Mühlkreis, Austria.

Burgruine Haichenbach is a medieval fortress ruin set on a hill above a bend in the Danube, near Hofkirchen im Mühlkreis in Austria. Sections of the original walls remain standing alongside a partly restored watchtower, showing the layout of a fortification built to oversee river traffic.

The fortress was first recorded in 1160 under the lords Otto and Wernher von Eichenbach, who used it to control movement along the Danube. Around 1529 it lost its strategic role and began the slow decline into the ruin visible today.

Locals call the ruin Kerschbaumerschlössl, after the nearby Kerschbaumer farm, because the castle's own name faded from memory after it was abandoned in 1529. The restored residential tower, with its ten original arrow slits, is freely accessible and gives a view over the Danube valley.

The ruin is reached from Freizell, not from Hofkirchen itself, which lies about 6.3 km to the northeast. Since 1984 restoration work by the Hofkirchen heritage committee has made the site safe to visit. The restored residential tower is freely accessible and gives a view over the Danube valley.

The castle's name faded from memory after it was abandoned in 1529: locals renamed the ruin Kerschbaumerschlössl after the nearby Kerschbaumer farm. The Passau bishopric withdrew the fief in 1516 after Danube boatmen complained about the Oberheimer family, who allegedly enriched themselves with excessive tolls.