
Borgen in Rø Plantage
This castle has probably been the major stronghold for the settlements in one of the island’s wealthiest areas in Iron Age and Viking times when residents were attacked from the sea. The name in English means “The Castle” (Borgen) or “Castle Head” (Borgehoved). Archaeologists estimate that Borgen could possibly date back to the late Bronze Age 2,500 years ago.
Borgen or Borgehoved is located in Rø Plantage, on the boundary between Rø and Østerlars Parishes and the county boundary between Nørre and Øster Counties. The fort lies 3.1 km from the coast in the forest plantation of Rø. Recently the trees covering the area have been cut revealing the original lanscape and stone walls.
It is built on a rocky plateau that forms a promontory at the junction of the northern and southern Borgdal valleys. Steep 12-m high cliffs make it almost inaccessible from the river valleys to the north and east. The wide access from the southwest is obstructed by an approximately 275-m long angled stone wall that runs 240 m in a north–south direction and 35 m in an east–west direction, enclosing 3.2 ha of fortress (Skaarup, 1985).
There seem to be three entrances to the fort, one in the northeast, one in the northwest and one in the southwest. A network of hollow roads leading to and from the fort is still preserved in the area. Water sources have been found within two places at the fort. The largest spring is in the northern part. The fort has been interpreted as uncompleted, but the presence of five monoliths and the many hollow roads indicate that it has been used. The fort remains undated and no archaeological investigations have been performed at the site. The first metal detector survey of the site was made in the autumn of 2012, but this only revealed half of a horseshoe from the Viking Period. A couple of the monoliths at Borgen have been the subject of individual preservation orders since 1943, while the remainder of the fort (i.e. the stone wall) is preserved as an ordinary visible ancient monument incompliance with the 1975 Nature Conservation Act. The area is owned by the Danish Nature Agency
Video showing the forest being cut down that had previously obscured the castle

Looking north on the southern side of the castle along Søndre Borgdal

Archaeologist Finn Ole Nielsen from Bornholm Museum shows the remains of the castle walls (Photographer Michael Stoltze)

Map from the beginning of the 1800’s

Borgehoved, Rø Parish, 1878 sketch by P. Hauberg
REFERENCES :
http://naturstyrelsen.dk/nyheder/2016/nov/skjult-borg-ser-dagens-lys/
http://naturstyrelsen.dk/naturoplevelser/naturguider/roe-plantage/sevaerdigheder/
http://tidende.dk/print/?Id=75596
http://www.367ture.dk/site/Noerre_Borgedal/