Arkham Asylum () is a fictional psychiatric hospital appearing in American comic books published by DC Comics, commonly in stories featuring Batman. It first appeared in Batman #258 (October 1974), written by Dennis O'Neil with art by Irv Novick. Located in Gotham City, the asylum houses patients who are criminally insane, as well as select prisoners with unusual medical requirements that are beyond a conventional prison's ability to accommodate. Its high-profile patients are often members of Batman's rogues gallery. History.
https://en.wikipedia.org/wiki/Arkham_Asylum