Arkham Asylum

The Elizabeth Arkham Asylum for the Criminally Insane, commonly called Arkham Asylum or simply Arkham, is a psychiatric hospital. Many criminals who experience psychosis from the DC Universe have been patients within the asylum and also escaped from it. Many of Arkham's high-profile patients are from Batman's rogues gallery.

Residents
Originally, Arkham Asylum is used only to house genuinely mentally ill patients having no connection to Batman, but over the course of 1980's, a trend was established of having the majority of Batman's supervillain opponents end up at Arkham.