Eisenacher Burg, Medieval castle ruins near Wartburg, Eisenach, Germany.

Eisenacher Burg is a castle ruin located near Eisenach on a steep forested hilltop, consisting of several rectangular building sections. The complex was reinforced with multiple defensive ramparts, and visitors can still examine rock-cut foundations and fortification structures today.

The Eisenacher Burg was a siege castle built during the Thuringian-Hessian War of Succession (1247–1263) to block the southeastern routes to Eisenach and the Wartburg. In 1306–1308 King Albert of Habsburg used it as a military camp while besieging the Wartburg; Count von Weilnau had towers, palisades and blockhouses erected, and a trebuchet damaged the Wartburg's palace and south wall. Weilnau was ambushed and died in captivity on the Wartburg.

The site reveals medieval defensive engineering that visitors can grasp directly while exploring the remaining walls and structures. The steep hilltop location still communicates how medieval builders chose and used strategic positions for protection.

The site is accessible year-round without entrance fees, allowing visitors to explore independently at their own pace. The steep approach requires sturdy footwear and some effort to climb, but the elevated location rewards visitors with wide views.

On the plateau, rock-cut sockets marked A to F on the site plan held wooden defensive towers, while G marks the bergfried and H the recess of the Blidenstatt, where a Blide (trebuchet) stood. Excavations in summer 1995 also found Iron Age settlement traces beneath the siege-era layers.