Burg Geldern, Medieval castle ruins in Geldern, Germany

Burg Geldern is a castle ruin located in Geldern along the Niers river, where the stone foundations remain visible today. The site sits directly on the Mühlenweg path and shows how the medieval fortress once controlled this river crossing.

Burg Geldern was first documented in 1237 as a seat of the Counts, later Dukes, of Geldern, built on an uninhabited island west of the later town to guard a Niers crossing. In the late Middle Ages it became an administrative seat and residence for travelling dukes. As power shifted to the Rhine delta in the 15th and 16th centuries, the castle was abandoned and later decayed; nothing survives above ground.

The castle gave Geldern its name and its start: the settlement that grew around the fortified crossing on the Niers became the town, and the counts and later dukes of Geldern took their title from it. Nothing of the castle stands above ground today, so the link survives mainly in the name and in the town's own account of its origins.

The site lies at the Mühlenweg in Geldern, west of the old town, where the excavations of 1964–1966 uncovered oak posts and wall remains. Nothing survives above ground, so look for the information boards that mark where the main castle and its 11.75 × 11.25 m foundation once stood.

The castle was built on previously uninhabited islands west of today's town centre. Dendrochronology of oak piles found during 1964–66 excavations at Ponter Straße 6 and Mühlenweg dates the timber to about 1353, placing construction in the mid-14th century. Older theories linking the counts' original castle to Aldekerk are now rejected.