The back story given by Mrs Blankenship about the haunted house the Prescott family move into is based on the real life case of Mudhouse Mansion. Mudhouse is located in Fairfield County, Ohio, United States, just east of the city of Lancaster. It is said to have been built in the 1870s. Incidents that allegedly occurred at the property include those mentioned in the film - the murder of a slave owner's family and a mass suicide by a family who later moved into the Mansion. Mudhouse Mansion has not been occupied since the 1930s and to this day is abandoned and remains closed to the public.
Update: Mudhouse Mansion, which was in fact occupied as recently as the 1960s, was demolished on September 21, 2015. All that remains are the stories. Despite local legend, no murders or suicides were ever confirmed to have occurred there.