Mystery Castle is located in the city of Phoenix, Arizona, in the foothills of South Mountain Park. It was built in the 1930s by Boyce Luther Gulley (died 1945) for his daughter Mary Lou Gulley. After learning he had tuberculosis, Gulley moved from Seattle, Washington, to the Phoenix area and began building the house from found or inexpensive materials. Boyce Gulley died in 1945, and Mary Lou and her mother were notified by attorney that they had inherited the property. Shortly after, the mother and daughter moved in.
Their story attracted national attention, giving the home some notoriety as well as its exotic name: A Life Magazine story (January 26, 1948) used the headline "Life Visits a Mystery Castle: A Young Girl Rules Over the Strange Secrets of a Fairy Tale Dream House in the Arizona Desert." The photograph featured Mary Lou posing atop the cantilever staircase leading to the roof of the house. That same year, Mary Lou and her mother began offering tours of the home.
Said to be held together by a combination of mortar, cement, calcium, and goat milk, the sprawling 18-room, three story castle is built from a wide range of materials—stone, adobe, automobile parts, salvaged rail tracks from a mine, telephone poles, etc. It features a chapel, cantina, and a dungeon. Parts of the castle remain unfinished, and electricity and plumbing weren't added until 1992. As the housing boom progressed in Phoenix, new development encroached dangerously close to the castle and it's grounds, making it far less "isolated".
Mary Lou Gulley passed away on November 3, 2010. There is a possibility that the State of Arizona may take ownership of this historic site.
The Mystery Castle has been designated as a Phoenix Point of Pride.