Hünselburg, Medieval castle ruin in Asel, Germany

Hünselburg is the site of a Celtic hillfort on the Lindenberg, a narrow, cliff-lined spur of the Kellerwald-Edersee National Park that the Edersee surrounds on three sides at high water. Only ramparts and ditches survive: three strong walls about 500 m apart cut off the spur to the north, and at least two section walls remain to the south, the two innermost being the best preserved.

The Hünselburg is a Celtic refuge castle from the early La Tène period, shown by pottery shards and glass beads found on the Lindenberg spur. Three strong ramparts about 500 m apart cut the spur off to the north, and at least two section walls remain to the south, the two innermost being best preserved. No medieval castle or noble family is recorded at the site.

The name Hünselburg is not medieval: the site is a Celtic refuge castle of the early La Tène period, dated by pottery shards and glass beads found on the Lindenberg spur. Three ramparts about 500 m apart cut the ridge off to the north, and at least two more section walls survive to the south, the two innermost being best preserved. The southern tip of the spur has been a 40-hectare nature reserve since 1977, first for a grey heron colony, now for near-natural woodland.

The ruins are freely accessible via a hiking trail, allowing visitors to explore at their own pace. The observation tower provides a good vantage point to understand the site's layout and survey the wider landscape.

The southern parts of the Lindenberg spur have been a nature reserve since 1977, covering about 40 hectares. The reserve was created for a grey heron colony that has since been abandoned; today it protects near-natural woodland of national importance and is left to develop without intervention.