Barenburg, Iron Age hillfort near Eldagsen, Germany

Barenburg is an Iron Age hillfort on a wooded spur of the Osterwald, about 3 km south of Eldagsen and 1 km west of Wülfinghausen Monastery. Its interior covers 5.5 hectares. On the south side, a 280-metre-long stone rampart with a ditch still stands several metres high; steep slopes and rock faces protect the other sides.

The Barenburg is a hillfort whose construction is dated by its layout and form to the pre-Roman Iron Age, though no excavation has taken place and an early medieval origin is also possible. It served as a refuge fort for the local population, a role that may have continued into the Middle Ages, as the site belonged to Wülfinghausen Monastery. Metal finds recovered after looting in 1988 show bent spearheads, notched sickles and torn belt hooks, which archaeologist Erhard Cosack links to an attack in the later Iron Age.

The name Barenburg has no recorded Slavic root; the site belonged to Wülfinghausen Monastery, which likely kept it in use as a refuge into the Middle Ages. Visitors can still trace the 280-metre stone rampart and its outer ditch on the southern side.

The site is located in a forested area and is best reached on foot from Eldagsen. The marked hiking routes are accessible year-round, though sturdy footwear is recommended due to the hilly and uneven terrain.

In 1988, looters offered Iron Age metal objects labelled "Barenburg, Niedersachsen" at a coin fair in Hanover; police traced them to a Berlin group and seized around 400 La Tène finds, later returned to research. The undocumented digging permanently reduced the site's source value.