Berggeistweiher, Protected area in Brühl, Germany

Berggeistweiher is a lake in southern Brühl, formed by the renaturation of the Grube Berggeist pit and entirely surrounded by forest. It lies at 137 metres on the Ville ridge near the A553 motorway and the Brühl-Süd junction, and parts of it are protected: 3.7 hectares in the Rhein-Erft-Kreis (BM-024) and 10.5 hectares in the Rhein-Sieg-Kreis (SU-010).

The lake was created by the reclamation of the Grube Berggeist, an open-cast pit on the Ville ridge south of Brühl. Parts of the water and the surrounding land are protected: 3.7 hectares in the Rhein-Erft-Kreis under code BM-024 and 10.5 hectares in the Rhein-Sieg-Kreis under code SU-010. From August 2023 the path on the south shore is closed and being removed to safeguard the reserve.

The lake takes its name from the former Grube Berggeist, the pit it now fills, and the Berggeiststraße running past it; 300 metres north on that road stands the Phantasialand leisure park (Berggeiststraße 31–41). Locals also call it Tonweiher, after the clay dug here.

The lake lies at 137 metres on the Ville ridge at Brühl's southern edge, near the A553 motorway and the Brühl-Süd junction. From August 2023 the path along the southern shore is closed and being dismantled to protect the nature reserve, so approach from the north. The water and its surroundings are split between two protected areas, BM-024 in the Rhein-Erft-Kreis and SU-010 in the Rhein-Sieg-Kreis.

The lake was created by rewetting the former Grube Berggeist open-cast pit, not by a wartime event. Two nature reserves meet here: the 3.7-hectare BM-024 in the Rhein-Erft-Kreis and the 10.5-hectare SU-010 in the Rhein-Sieg-Kreis. From August 2023 the path on the south shore is closed and being dismantled to protect the habitat.