In the Black Forest, an abandoned silver mine tunnel was converted into an earth observation laboratory by the Karlsruhe Institute of Technology and the University of Stuttgart in 1971, named Black Forest Observatory (BFO). Over 30 sensors are equipped for earth observation in BFO. As BFO was originally a mining excavation, there is no accurate map available to represent its structure. To enable effective planning and implementation of a geosensor network that integrates both existing and new sensors, a precise and accurate map of the BFO tunnel is needed. This study investigates a control point based approach for 3D mapping of the BFO tunnel using laser scanning technologies. A georeferenced network of 33 control points was established using total station measurements to support terrestrial laser scanning (TLS) and mobile laser scanning (MLS). Based on the control point network, this study builds a ground truth TLS point cloud map for the BFO tunnel and integrates and evaluates the MLS point clouds. The map in BFO over 50 years is also compared. The results demonstrate that the established control network achieved millimeter-level precision, providing a robust framework for TLS mapping. Comparison of the MLS point cloud with the TLS ground truth revealed a drift of the MLS point clouds in the tunnel environment. Furthermore, comparison with historical data from 1972 confirms overall structural stability, supporting the tunnel’s continued use for long-term geoscientific research.