This map was published in the official DC Role Playing Game in 1990, and locates all East Coast cities that feature in DC Comics, including Gotham City and Metropolis. No sign of Blüdhaven, though, which miraculously sprouted from the ground in the early 2000’s.
I guess, with the DC titles glut of recent years, a map like this now would have to be some kind of 3D affair, with all earths on different planes.
Just thinking about this gives me a headache. More here.