Burg Beyernaumburg, Medieval castle ruins in Allstedt, Germany.

Burg Beyernaumburg stands on a mountain ridge near Allstedt and shows the remains of medieval fortifications. A tall tower and a deep moat surrounding the grounds give visitors a sense of how the stronghold once defended the area.

The site received its first written record in the 9th century under the name 'castellum Nivanburg'. Over the following centuries, the fortress served military and administrative purposes in the region.

The castle park was laid out by Friedrich von Bülow (1760–1831) and later planned by the landscape gardener Eduard Petzold. In the park are several graves of the von Bülow family, who held the estate until Hans Freiherr von Bülow was expropriated in 1945. The last owner died in 1979 in Wendlinghausen.

The surviving 30-metre bergfried stands in the outer bailey, separated from the former core castle by a moat; the neo-Gothic schloss replaced the main castle in 1865 and is privately owned, so visits focus on the tower and the surrounding park with its von Bülow graves.

In 1308 Archbishop Burchard III of Magdeburg ordered the arrest of the Templars of the Halberstadt diocese; the Templars of the Harz region withdrew to Beyernaumburg and barricaded themselves there. Burchard besieged the castle and converted two nearby churches into fortifications for his troops. Bishop Albrecht I of Halberstadt responded by placing the archbishop under church ban, an unprecedented step, and Burchard lifted the siege and granted the Templars free passage.