At some point around 1920 - 1928 a tower was added to the top of the mountain. It was originally a water tower erected on the site of what is now the Wanaque Reservoir, built in the early 1900s by Clifford MacEvoy. Mr. MacEvoy relocated the tower to Ryecliff and enclosed it in mountain stone so as to blend in with the house itself as well as the natural environment. The Observation Tower stands high at a ground elevation of . Its five stories include two floors with toilet and, on the fifth floor, the room contains a fireplace. A hatch on the fifth floor leads to a roof with incredible views of Ramapo Park and Lake, the Wanaque Reservoir, mountains to the west and to the east, New York City.