- For other uses, see Chicago.
During the early part of the 1920s, organized crime became a powerful fixture in the city of Chicago, to the point that conventional city government nearly fell apart. In the early 1990s, Pocket Books published a book titled Chicago Mobs of the Twenties, detailing the history of the Mob during that time period. A copy of the book later was left on the planet Sigma Iotia II by the Earth ship USS Horizon. The Iotians saw the society depicted in the book as a perfect society, and rebuilt their society along those lines. (TOS episode: "A Piece of the Action")
During the year 2259, Chicago was one of many cities to construct many star ships vessels during the time. Under the orders of Alexander Marcus, The USS Vengeance was constructed to be the most powerful in any other starship. (TOS - Khan comic: "Issue 4")
In 2251, James T. Kirk guessed that Gary Mitchell was either from Chicago or Detroit. He was wrong on both counts, as Mitchell was born and raised in New York City. (TOS - My Brother's Keeper novel: Republic)
In 2279, Starfleet assigned the USS Enterprise to a time travel mission to return to 1983 and prevent Earth's Icarus plague. However, the USS Enterprise inadvertently arrived in an alternate timeline. In that timeline, James T. Kirk, Spock, and Montgomery Scott beamed down to Chicago to confirm that they were at the right point in 1983. Immediately two boys recognized them, thinking at first that they were characters from the Star Trek TV series, then realizing they were from the 23rd century. The two Chicagoans were beamed aboard. Later the boys tried to escape by stealing a two-man shuttlecraft. (TOS comic: "Getting Real")
Lieutenant Barbara Brinson once participated in a time travel mission to 1920s Chicago, during which she was able to reboot the time stream by reversing the polarity. (LD episode: "Cupid's Errant Arrow")
In the mirror universe, Chicago was one of the cities devastated in a brazen attack by alien rebels against the Terran Empire in 2155. Empress Sato I visited Chicago following the attacks, where she was surprised to find the citizens' anger directed at her. (ENT - Mirror Universe novel: Age of the Empress)