The Poppenberg is a tree-covered hill east of Ilfeld in the Harz mountains of Germany, at an elevation of 601 metres.

The tower was built by the Nordhausen branch of the Harz Club and was named after Otto, Prince of Stolberg-Wernigerode.

[1] In good weather, it has an extensive view over the South Harz, the Goldene Aue and the Kyffhäuser.

Today, it lies in the free state of Thuringia and is the highest elevation in the Thuringian part of the Harz.

[1][2] The Poppenberg is situated east of Ilfeld, in the Harz mountains, in the state of Thuringia.