From Haunted Colorado: (visit link
Yes, the Richthofen Castle is indeed haunted; according to the book, "Denver's Richthofen Castle" by O.J. Seiden (1980, Stonehenge Books/Enkidu Press).
O.J. Seiden was a previous resident of the castle. In this book, he mentions friendly spirits in the old castle.
He and his family experienced many unexplainable events in that house. They always heard footsteps on the 2nd floor-- when there was no one there. Their dogs refused to go up on the second floor for a day or two after the sound of footsteps was heard.
Items also vanished and were not where they had put them. Then the object would end up in very unlikely places, sometimes days or weeks later.
There is also a spirit in the tower. The Seiden family noticed coming home one night that there was a light on up in the tower. But there is no electricity or lights up there. Then they thought that someone had gone up there. But-- there were absolutely NO footprints in the snow! They went up there- and no one was there.
From the Colorado State Register of Historic Properties: (visit link
Completed in 1887, the 21-room residence was built on the prairie fifteen miles east of downtown Denver by real estate promoter Baron Walter von Richthofen as a show home for his Montclair development. Originally fortress-like in style, additions and modifications designed by Maurice Biscoe in 1910 and Jules J.B. Benedict in 1924, resulted in an English Tudor appearance. The walls, towers and parapet are of Castle Rock rhyolite, and the estate is contained within an acre of walled gardens.
From The Free Library: (visit link
Undaunted, Richthofen proceeded with the five-year construction of his castle on a 320-acre lot in Montclair, a Denver suburb he helped develop. Referred to within the family as Louiseburgh, after his second wife, the manor house was and remains generally known as Richthofen Castle. The gray, crenellated 21-room mansion featured towers, a quaint stone bridge over a moat and a landscaped garden stocked with deer, antelope and wild canaries. The superb timing of his real estate enterprises in East Denver and Montclair allowed Richthofen to keep afloat and bask in some luxury despite the hit he took when the cattle business failed due to the climate. Walter and Louise moved into the castle in 1887 and lived there happily ever after--for three years.
The story goes that the Baroness didn't care for the look of the prairie around the castle, so the Baron had many trees planted on and around the estate. Which is why it is now difficult to see and photograph the castle during the greener months and not much easier during the winter.