The Upper Harz is the northwestern and higher part of the Harz mountain range in Germany. The exact boundaries of this geographical region may be defined differently depending on the context. In its traditional sense, the term Upper Harz covers the area of the seven historical mining towns (Bergstädte) - Clausthal, Zellerfeld, Andreasberg, Altenau, Lautenthal, Wildemann and Grund - in the present-day German federal state of Lower Saxony. Orographically, it comprises the Harz catchment areas of the Söse, Innerste and Grane, Oker and Abzucht mountain streams, all part of the larger Weser watershed.

The Harz 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-Anhalt, and Thuringia. The name Harz derives from the Middle High German word Hardt or Hart. The name Hercynia derives from a Celtic name and could refer to other mountain forests, but has also been applied to the geology of the Harz. The Brocken is the highest summit in the Harz with an elevation of 1,141.1 metres (3,744 ft) above sea level. The Wurmberg is the highest peak located entirely within the state of Lower Saxony.