Arkham Asylum was a dark and gloomy facility for the criminally insane in the Somerset District of Gotham City.
The asylum resembled a prison more than a sanatorium. In addition to the insane, Arkham was also specially equipped to house prisoners with unique medical or environmental needs, who could not be otherwise incarcerated in Stonegate Penitentiary. For instance, Victor Fries, who could not survive outside of a sub-zero environment, was housed in a special freezer cell that allowed him to survive without his special cold suit.
Arkham was notorious as the "home" of many of Batman's greatest foes, and was reputed to have both airtight security and some of the world's best psychological experts on staff. However, over time, both of these claims have proven to be false. In addition to few improvements in patients' conditions, inmates were constantly escaping, and at least two staff members—Dr. Harleen Quinzel and Lyle Bolton—are known to have been driven insane and later became inmates themselves.
The structure was built on top of a large underground cavern, and took its water from a river flowing beneath it.
On one occasion, the inmates of Arkham staged a takeover of the asylum and used one of the operating theatres as a mock-courtroom, to hold a "trial" of a captured Batman.
According to Barbara Gordon, the asylum's inmates and facilities were relocated to a newer, more modern facility elsewhere sometime before the 2030s. While the old asylum was partially demolished, the rest was allowed to decay. The ruins of the old asylum were the site of the last, worst confrontation between Batman and the Joker, which the latter did not survive. His remains were buried, secretly, under Arkham. Harley Quinn was also thought to have possibly died from a fall in the ruins, but as her body was never recovered the heroes believed years later that she could still be alive as they were, but harmless. Unknown to them, this hypothesis was correct.
In the Justice Lords' alternate universe, the asylum was run by a lobotomized version of the Joker and was protected by robotic copies of Superman. The entire inmate population was lobotomized by their world's Superman's heat vision.
- Dr. Bartholomew
- Dr. Joan Leland
- Dr. Harleen Quinzel (committed)
- Irving (temporary)
- Lyle Bolton - Chief of Security (committed)
- Batman (temporary)
- Emile Dorian
- Mister Freeze (deceased)
- Harley Quinn
- The Joker (deceased)
- Killer Croc
- The Mad Hatter
- Poison Ivy
- The Riddler
- The Scarecrow
- The Ventriloquist
- Maxie Zeus
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