Bunkenburg, Archaeological site in Lower Saxony, Germany.

Bunkenburg is an oval-shaped fortification in Lower Saxony with a surviving rampart section standing about 3 meters high. A state road built in the 1980s divides the archaeological site, with the northern portion containing the better-preserved defensive wall.

Bunkenburg was built in the 13th–14th centuries as a lowland ringwork on the Aller's north bank, securing the water route at the border of the Principality of Lüneburg and the Bishopric of Minden. It replaced Bierde castle in this role. In 1310 Burgmannen including the lords of Ahlden and Burgvogt Johann von Escherde are recorded; the last mention is in 1340, after which the Burgmannen moved to Rethem.

The name Bunkenburg probably derives from Bunke, the common term for the bog iron (Raseneisenstein) used as building material. The site is now a private residence on the southern rampart section: a brewery built around 1700 by the prince's household, privatised only in the 19th century and run as a drinks business until the mid-20th century.

The site is accessible but divided by a modern road, which is important to keep in mind when exploring the full structure. The northern section is easier to reach and provides the best views of the surviving rampart.

Excavations in 1976 and 1982 uncovered pottery fragments from the 9th to 11th centuries, pointing to extended human settlement at this location. These findings reveal the site was used far longer before its later role as a medieval fortress.