Trelleborg ring fort, Viking ring fortress in Trelleborg, Sweden

Trelleborg ring fort is a Viking ring fortress in Trelleborg, Sweden, built around 980 with a diameter of 140–143 m. Its reconstructed northwest quarter has an earthen rampart topped by an oak palisade, a 2 m deep and 4 m wide ditch, and a gatehouse in stave construction with a Romanesque balcony. A 14th-century half-timbered house and a farm with outbuildings stand on the site.

Built around 980 during the reign of Harald Bluetooth, the fortress was abandoned after about 20 years as Wendish raids increased. The site lay forgotten until excavations in 1988 uncovered the north and west gates and sections of the rampart and ditch. The northwest quarter was reconstructed by 1995.

The name Trelleborg has three proposed explanations: a fortress built by thralls (Old Norse træll), a slave-trading site, or a reference to the split beams called treller used in the palisade. The site hosts a Midsummer celebration and Viking camps several times a year.

The site is easy to explore on foot, with clear paths and well-marked areas throughout the reconstruction. A café and gift shop on-site allow visitors to spend time comfortably and have refreshments available during their visit.

The wooden structures were rebuilt using only historical tools and techniques, with workers relying on axes, knives, and methods that Vikings would have used themselves. This hands-on approach reveals the skill and labor required to construct such a large defensive structure.