The film is shot on location in the real Eloise Insane Asylum, which used to be one of the largest mental institutions in the world. It began as one building in Westland, Michigan in 1832, before rapidly growing into a 78-building complex, complete with its own fire and police departments, train station, post office and farms. The asylum finally closed in 1982, and has since been used as many things such as a daycare center, a homeless shelter, and a business office. Many of the outlying buildings such as the bakery, firehouse, tavern, and powerhouse are in ruins beyond repair.
Eloise at one time had its own zip code because it was given a post office on July 9, 1894.
The potters field on the grounds of the Eloise contain the unidentified remains of approximately 7,100 former residents of the hospital and asylum.
Successive presidents of the Westland Historic Village (a museum) have worked with genealogists and families to attempt to identify the dead. It is believed that approximately 1% have been identified.
Unfortunately, many of the patients buried in potters field were John and Jane Does, so their real identities were never known. Also the graves were dug haphazardly, with many of them dug on top of each other and only marked with brick bearing an ID number, meaning the only way to identify a body is by searching 150 years of patient records to match the number to a name. As the field was left untended for decades, it became so over-grown a large number of markers have been lost, and with them any hope of discovering whose remains are in the graves.
The film repeats the oft made claim that the Eloise was the site of the first x-rays. However, the x-ray was invented in Bavaria, Germany and the first performed under clinical conditions were in England.
The Eloise asylum; named after the daughter of Detroit's Postmaster, began its long and horrifying history as a poorhouse and farm.
The Eloise Psychiatric Hospital itself was a collection of buildings housing the hospital and asylum, (including nurses quarters and its own post office) surrounded by a growing complex. Eventually becoming a completely self-sufficient compound.
Although it officially closed in 1981, some administrative buildings continued to be used; as they are in the film, up until 2016.
The 5 buildings in the film are all that remain of the compound, and were sold by the county for $1.