Illinois is a region of the North American continent on the planet Earth, with boundaries that were created as the area was settled as a geopolitical subdivision of the United States of America nation.
The city of Chicago, which was one of the largest cities in the United States, was located in the northeastern corner of the state. During the early years of the 20th century, the mob in Chicago became very powerful, to the point that the conventional government of Chicago nearly broke down. (TOS episode: "A Piece of the Action")
In 2372, Traveler Wesley Crusher transported Will Riker to 1950s Illinois to meet jazz legend Stan Kenton as a birthday gift, which Riker thought was a holodeck program. (TNG - Strange New Worlds VII short story: "Adventures in Jazz and Time")
The Federation starship USS Enterprise time traveled to Earth in 1983 but inadvertently arrived in an alternate timeline. When James T. Kirk, Spock, and Montgomery Scott beamed down to Chicago, two boys recognized them as characters from the Star Trek TV series. (TOS comic: "Getting Real")
In 2155 of a mirror universe, Chicago was attacked by aliens rebelling against the Terran Empire. Empress Sato I visited Chicago following the attacks. (ENT - Mirror Universe novel: Age of the Empress)
- Joey (1983) (Chicago) 
- Abraham Lincoln (Springfield) 
- Malcolm (1983) (Chicago) 
- Rianna Mayweather (Chicago) 
- B.G. Robinson (Metropolis) 
Points of interest
- Fermilab 
- Illinois State University 
- Sears Tower
- University of Chicago  
- Wrigley Field 
|Geographical regions of the United States of America|
|States and districts||Alabama • Alaska • Arizona • Arkansas • California • Cibola • Colorado • District of Columbia • Connecticut • Delaware • Florida • Georgia • Guam • Hawaii • Idaho • Illinois • Indiana • Iowa • Kansas • Kentucky • Louisiana • Maine • Maryland • Massachusetts • Michigan • Minnesota • Mississippi • Missouri • Montana • Nebraska • Nevada • New Hampshire • New Jersey • New Mexico • New York • North Carolina • North Dakota • Ohio • Oklahoma • Oregon • Pennsylvania • Puerto Rico • Rhode Island • South Carolina • South Dakota • Tennessee • Texas • Utah • Vermont • Virginia • Washington • West Virginia • Wisconsin • Wyoming|
|Geographical and cultural regions||Midwest • New England • Pacific Northwest • The South|
- FASA Corporation published their books out of Chicago.
- A number of Star Trek creators reside in Illinois:
- Chicago Mobs of the Twenties
- USS Chicago (NCC-1651)
- USS Chicago (NCC-2738)
- USS Chicago (24th century)
- USS Elgin
- Illinois article at Memory Alpha, the wiki for canon Star Trek.
- Illinois article at Wikipedia, the free encyclopedia.
- TOS comic: "Getting Real"
- Historical accounts
- ENT novel: Kobayashi Maru
- ST video game: Starship Creator
- ST reference: The Physics of Star Trek
- TOS episode: "A Piece of the Action"
- TOS novel: Sarek
- TOS - Star Trek: Assignment: Earth comic: "My Name Is Legion"
- Decipher RPG module: Worlds
- ST reference: Federation: The First 150 Years
- DS9 novel: Bloodletter
- DS9 episode: "Emissary"