Nonnenstein is also the name of a 14-metre-high observation tower on the hill (officially: Aussichtsturm auf dem Nonnenstein or Viewing Tower on the Nonnenstein). The tower was erected in 1897 as an Emperor William Tower. The Nonnenstein lies exactly on the boundary between the counties of Minden-Lübbecke and Herford. Originally it was lower; at the end of the 20th century the tower was raised in height due to the increased height of the trees. There is a stylised depiction of the observation tower on the Nonnenstein on the coat of arms of Rödinghausen.