Hahausen is a village and a former municipality in the district of Goslar in Lower Saxony, Germany. Since 1 November 2021, it is part of the town Langelsheim, of which it is an Ortschaft.

The Harz, also called the Harz Mountains, is a highland area in northern Germany. It has the highest elevations for that region, and its rugged terrain extends across parts of Lower Saxony, Saxony-Anh