Allerton Mansion in Monticello, Illinois, is rumored to be haunted by a Lady in White who is believed to be a former guest of the mansion. Sightings of her spirit have been reported in the mansion's guest rooms, near the pond, and on the stairs. The Lady in White: This spectral figure is said to be a long-ago resident or visitor to the mansion. Her presence is most often described in places she might have frequented, including her guest room, the area by the pond, and on the main staircase. The Georgian Revival mansion was built in 1900 as the private estate of artist and philanthropist Robert Allerton. The mansion and the surrounding Allerton Park are open to the public.