Hünenburg Hohenrode, Medieval castle ruins in Rinteln, Germany.

The Hünenburg, also called Frankenburg, is the ruin of a small medieval dynastic hill castle on a southern spur of the Lange Wand in the Wesergebirge, about 230 m above sea level and 1.6 km north of Rinteln station. Its oval core castle measures 27 by 35 m and was enclosed by a mortared ring wall 1.5 to 2.5 m thick, against which the buildings leaned. Foundations of the residential tower, the palas and a castle chapel with remains of opus spicatum masonry are visible, and the excavated foundation walls have been restored. A five-metre-deep ditch separates the core from the uphill outer bailey, which is protected by a seven-metre-deep moat and a ring wall and still shows the remnant of an unexcavated round tower.

The builders and occupants are unknown, so the name was assigned later. Excavations by Konrad Plath in 1895 and 1897 found pottery sherds and horseshoes pointing to use between the late 11th and the end of the 12th century, plus coins minted in Goslar around 1080. Its end coincides with the establishment of the Counts of Schauenburg in the Weser valley, and fire damage in the walls is probably their work.

The name Hünenburg was given later, since the builders and inhabitants are unknown; the castle is also called Frankenburg after the Rinteln locality below it. Visitors can still see the restored foundation walls, the five-metre-deep ditch dividing core castle and outer bailey, and the surviving opus spicatum masonry of the castle chapel.

The ruins lie on a roughly 230 m high southern spur of the Lange Wand, reached on foot from Rinteln or Todenmann; the ground is uneven and the slope toward the Weser falls away steeply. The core castle is separated from the outer bailey by a five-metre ditch, and a seven-metre moat and ring wall protect the hill side.

Excavations by Konrad Plath in 1895 and 1897 uncovered pottery shards and horseshoes pointing to use between the late 11th and late 12th century, plus coins minted in Goslar around 1080. The name Hünenburg was given later, since no builders or inhabitants are known.