St. Jansberg is a nature reserve (Natura 2000) and former estate in Plasmolen and Milsbeek in northern Limburg. One of the hills in the area is called St. Jansberg also Kloosterberg.
St. Jansberg connects the Mookerheide with the German Reichswald and is bounded on the east by the Groesbeek community and is bounded to the west by the N271. The area has been a moraine in the last ice age. The Jansberg is the only place in the Netherlands, where the position of a glacier tongue from the crack ice age (Salien) was adopted. The area is a terminal moraine and is part of the area that used to be the Ketelwald. Since 1970, the former estate is managed by nature.
Bronbeek in St. Jansberg
The area is characterized by wooded hills and many streams. There are also some wetlands (The Geuldert, Die Diepen and King Sven) at the foot of the Jansberg. The two highest slopes are Kiekeberg (77 meters) and Saint Martin Berg (66 meters). Some apartments are in use for agriculture. In Plasmolen is a small dam and allows the upper Plasmolen, an old watermill. The Jansberg is about 250 hectares.
On the Jansberg are found remains of a Roman villa. The Pieterpad along the field. Parts of the area are not accessible because there are badger paving stones.