The Harlyberg, at , is the highest hill of the Harly Forest, and rises in the district of Goslar in southeastern Lower Saxony, central Germany.
Sometimes the term Harlyberg is used as a synonym for the entire Harly Forest (), but this ignores the fact that there are other summits in that forested hill range.
The hill is located just under 2 kilometres northwest of Vienenburg. It may be reached on various forest tracks and hiking trails that run through the Harly Forest - for example on the Kammweg ("ridgeway"). Almost exactly 2 kilometres southeast is the site of an old castle, the Harlyburg.
On the summit of the Harlyberg stands the Harly Tower (Harlyturm), an observation tower that was re-opened to tourists in 1986 after decades of decay and following major restoration. It is open when the flag is raised above its roof.
From the observation platforms â one glazed and one open one â of the Harly Tower there are views of the Harz Mountains to the south, the Elm to the north and the Huy to the east.