Comic Book Info: Opal City is a fictional city set in the DC Universe. Created by James Robinson and Tony Harris, Opal City first appeared in Starman vol. 2 #0 (October 1994). "The Opal" has been established as the home of several DC Comics characters, most notably several super-heroes who have operated under the name of Starman. Other, non-Starman related heroes who have come to call Opal City their home are the second Black Condor and the Phantom Lady, as mentioned in Teen Titans vol. 3 #20, as well as the Elongated Man. The city itself is first mentioned in Action Comics #251, April 1959 as the name of a ship, the S.S. Opal City which Superman rescues from a modern-day pirate crew. It can be inferred[weasel words] that Robinson named the city due to his vast knowledge of obscure comics continuity from both the Golden Age and the Silver Age.
Location: Depictions of Opal City in the Starman series showed it as a generally Eastern-US city with a port (though not necessarily a seacoast) and being surrounded by generally flat terrain. Mid-2000s (decade) issues of the JLA series, specifically 2005's "Crisis of Conscience" arc, have explicitly established Opal City as being located in Maryland,per Robinson's longstanding opinions on the subject in various interviews with fans.
History: Opal City is particularly notable for several aspects of its depiction in the second Starman series. The original settlement, "Port o' Souls", was established by Puritan settlers in the early 18th century. In 1884, the town elected Brian "Scalphunter" Savage as sheriff. About the same time the morally ambiguous Shade made Opal City his home.
The modern Opal City had its greatest expansion in the 1910s to 1930s, as evidenced by its many Art Deco buildings. An interesting detail is that the city, from its foundations, was heavily tainted with dark magic, first due to the activities of an unholy cult calling themselves the Tuesday Club, which was composed of Opal City's most influential and powerful citizens, from its beginnings as Port O'Souls in the Elizabethan era until Savage killed almost the entire cult the final night of 1899. Savage was killed by the last surviving member, but this man was killed seconds later by Savage's assistant, Carny O'Dare. Little after the foundation of Port O'Souls came the curse of the Black Pirate, binding all souls that ever died in Opal City to the earthly plane. The pinnacle of this was Hawksmoor St. John, the architect who planned Opal City's great expansion, also a fervent Satanist, who christened several buildings in blood so the lines drawn between them formed a perfect five-pointed star. In the World War II years, a group of Nazi occultists planned to drown Opal City into a void dimension, but the ritual was partly stopped by Etrigan and the then-Starman Theodore Knight. However, the aftermath of all of this was an atmosphere tremendously saturated in magical power, which the villain Simon Culp sought to use in conjunction with his own augmented power to create an impenetrable dome of shadow matter over the city, blocking all outer interference. He wished to allow the Nazi ritual to be completed, to destroy what his archenemy Richard Swift, the Shade, loved most. However, Culp was defeated and the souls liberated from the Pirate's curse.
It was in 1939 that the first Starman Ted Knight began his career as a superhero. Opal City itself at one point in its history suffered very heavy damage, first by explosions leveling several large stores, courtesy of the Infernal Doctor Pip, and later, due to the same man, demolition bombs designed to destroy much larger sections of the city during Culp's attempted destruction of Opal City. Additionally, the Post Office/Government building was torn out of its foundations and taken into space by Ted Knight, to protect the city from a nuclear bomb planted deep within it by the Mist. The bomb safely exploded in outer space, and the reconstruction of Opal City started.