The Oberhagen is a forest area of about 13 hectares, which has been placed under nature protection mainly because of its rich occurrences of protected plant species. In particular, the rare Turk's cap lily (up to 2,000 specimens; the northwesternmost occurrence) should be mentioned here.
The Oberhagen is also of enormous historical importance: iron ore has been mined here since the Middle Ages - two deep pits still bear witness to mining times. Oberhagen is home to one of the most important mining ground monuments in the Sauerland region, the collapsed pits and the shafts of the former Rom mine, which are up to ten meters deep and are fenced off for safety reasons.
Limestone was quarried on the west side until the 1970s, when operations near the city center had to be terminated for safety reasons. From 2005 onwards, the Oberhagen once again became the focus of local attention when the plan was pursued to remove more than 30m of the eastern quarry wall. In this way, the area for a prospective shopping center was to be expanded on the former quarry site. This plan met with resistance - among others, the "Initiative Oberhagen" was founded in 2006 - and was abandoned.
Especially in the spring months, this small grove unfolds its flowering splendor (visitors are asked to be considerate).