Per a 1908 decision by Chicago's city council, Madison serves as the north–south dividing line for Chicago's street numbering system, while State Street serves as the east–west line.[2] At one point, the intersection between the two streets was considered the "world's busiest corner."[3]
Madison Street was one of the "Big Five" streetcar lines of Chicago in the early-to-mid 20th century, which carried the most passengers, had the shortest intervals between cars, and had two-car trains in contrast to the typical one-car Chicago streetcar the most often.[6] Madison Street was home to some of the earliest transit in Chicago, having a horse car service starting from 1859.[7]Cable cars operated on the street until they were replaced by streetcars on August 19, 1906.[7] This line was formally codified as Through Route 20 (TR 20) in July 1921.[7] Two-car motor-trailer trains ran on Madison from October 14, 1923, to July 19, 1930; multiple-unit control trains began on an experimental basis on July 13, 1924.[6] A branch line diverging from the main service on Fifth Avenue joined the main line downtown starting August 19, 1906, after having previously been a shuttle; staying a shuttle during the night, it reverted to that status on Sundays starting April 24, 1932.[8] As of 1928, the main line had owl service between 1:01 and 5:20 a.m., during which cars ran for every ten minutes, but the Fifth Avenue branch did not, the last eastbound through-route car departing its western terminus of Crawford Avenue at 12:40 a.m. and the last westbound shuttle departing Madison at 2:00 a.m.;[9] during the day, streetcar lines in Chicago typically had intervals of between eight and fifteen minutes.[6] Buses replaced main line streetcars on weekends starting May 11, 1952 – simultaneous with the Fifth Avenue branch's replacement by buses on Saturdays – and altogether on December 13, 1953, whereupon the Fifth Avenue branch became a shuttle service at all times before it too was discontinued on February 22, 1954.[10]