Keystone City is a fictional city in the DC Comics. Specifically, it is the home of both the original Flash, Jay Garrick, and the third Flash, Wally West. Keystone City first appeared in the 1940s in the original Flash series. Within the comics, Keystone has been described as being "the blue collar capital of the United States" and a center of industry.
- In Batman: Arkham Asylum, Keystone City is referred to as a place where Amadeus Arkham went to college.
- In Batman: Arkham City it is mentioned that a similar prison will soon be opening in Keystone City and Metropolis.
- In Batman: Arkham Knight, a Militia soldier says "I'd choose Gotham over Keystone any day. At least you can see Batman coming." This hints that Wally West the Flash exists in the Arkhamverse.
- Also in Arkham Knight, there are several posters around Gotham stating "Run to Keystone City," showing a red streak traveling across a freeway, yet another hint at the Flash.