The Chicago station opened on October 17, 1943, as part of the State Street subway, which forms the central portion of what is now the Red Line between and stations. During the 1950s, the CTA implemented
skip-stop service throughout the 'L' system. Under this service pattern, Chicago was designated as AB along with all other downtown stations (on the Howard-Englewood-Jackson Park Line, those stops south of and north of were given AB designations). As a result, all trains stopped at these stations. Skip-stop service ended due to a decline in ridership in the 1990s.
Renovation From 1999 until 2001, Chicago underwent renovation and refurbishment, in line with other stations of the State Street subway. Work included making the station accessible to people with disabilities, with new elevators, redone flooring, retiling, and increased mezzanine space. Unlike most State Street Subway stations, Chicago uses a side platform configuration with two tracks, also used at
Grand/State and . There are entrances from street level at all corners of the intersection of North State Street and Chicago Avenue. One level below street level is a mezzanine containing fare controls and
turnstiles, and the platforms are located beneath the mezzanine. ==Bus connections==