Collenburg, Medieval castle ruins near Dorfprozelten, Germany.

Collenburg is a castle ruin located on an elevated position above the Main River near Dorfprozelten in Bavaria. The remaining stone walls clearly show the layout of defensive structures and buildings from medieval times.

The castle was first documented in 1214, when Walter von Schüpf, also called Walter de Colbo, was named as its builder and owner. After Walter's death in 1268, his widow transferred the Collenburg to the Teutonic Order, from which Wipertus Rüde de Rüdenau took it as a fief. The Rüdt family line resident at the castle died out in 1635, and in 1648 the Archbishopric of Mainz enfeoffed Nikolaus Georg von Reigersberg with it. Around 1750 the Counts of Reigersberg moved to Schloss Fechenbach, after which the castle fell into ruin.

The name comes from the noble family that once ruled this place, and traces of medieval fortification remain visible in the landscape today. Visitors can imagine how inhabitants watched over the valley and trade routes from this vantage point.

There is no public road access; the ruin is reached on foot by a narrow, steep serpentine path from the Forsthaus Fechenbach, about one kilometre east of Fechenbach. The Maintalhöhenringweg, marked "R", and the Fränkische Marienweg pass the site. The ruin is hidden by dense growth and visible from the valley only in winter.

After abandonment, the castle was briefly used as a forester's residence before eventually deteriorating into the ruins seen today. This unusual secondary use actually helped preserve some structures that might otherwise have been completely destroyed.