Oberhagen, Protected area in Warstein, Germany.

Oberhagen is a protected woodland area covering 14 hectares between Warstein's center and Suttrop district, composed mainly of mixed deciduous forest with oak and hornbeam trees. An asphalt road passes through the site, dividing it into distinct sections.

The area received formal protection status in 1985 to preserve its natural resources. Additional conservation measures were introduced in 2005 by the Arnsberg district government.

The site attracts nature observers interested in spotting rare plant species within its boundaries. Visitors walking through the forest can experience the variety of habitats that make this place special for those interested in woodland ecology.

The site is walkable and suitable for forest hikes through its natural corridors. The southern section displays visible traces of past mining activities that can be observed along walking routes.

The 2006 survey counted over 2000 Martagon lily specimens in the Oberhagen, but only 15 in the neighbouring Unterhagen, a 1600 m² limestone patch spared from quarrying about 170 m west. The Unterhagen also holds larger stands of barberry.