Pilgrim Psychiatric Center, originally known as Pilgrim State Hospital, is widely believed to be haunted due to its grim history, large-scale deinstitutionalization, and the abandoned remains of the former psychiatric hospital. The reports of paranormal activity include sightings of ghosts, unexplained sounds, and feelings of dread. Opened in 1931, Pilgrim was once the largest psychiatric hospital in the world, with a peak of nearly 14,000 patients in 1954. The vast campus functioned as its own self-sufficient community, with a police force, fire department, cemetery, and power plant. The sheer number of patients and the isolated, institutionalized environment contribute to the eerie atmosphere. In the 1950s, the hospital used aggressive and controversial "therapies" like lobotomies and electro-convulsive therapy (ECT). The controversial and often devastating effects of these procedures on patients' well-being are cited as a source of trapped and disturbed spirits. Some accounts from former staff members and others suggest a history of patient mistreatment and neglect, particularly as staffing was reduced over time. These reports fuel the narrative of tormented souls wandering the property. The hospital had its own cemetery for unclaimed bodies, and rumors of mass graves have long circulated. The thought of so many people dying and being buried on the grounds, sometimes without proper burial rites, is seen as a reason for hauntings. Visitors and urban explorers have shared numerous stories of paranormal encounters. The reported activity includes: Apparitions of former patients have been seen in the now-demolished admissions and surgical buildings. Moans, rattling doors, and metallic scraping have been heard within the abandoned sections. Some people have reported hearing voices that seem to follow them. Feelings of intense dread, temperature drops, and the sensation of being watched are commonly reported. Some have noted strange smells in the abandoned areas. Some paranormal investigators believe the sheer volume of pain and suffering within the institution left a spiritual "residue" that can still be felt by visitors.