I got so caught up in Parker Day yesterday I forgot to mention this bit of history:
[A] century ago Tuesday, on Sept. 1, 1909, State and Madison Streets became the base line of a new citywide grid system that changed virtually all addresses and also formed the basis for the street systems of many suburbs.
[Before then, t]he winding, bending Chicago River was the original start of the grid, but that meant addresses weren't consistent because they weren't based on a straight line, said Tim Samuelson, the city's cultural historian. When buildings were added, the city sometimes gave them numbers out of order. Street names were duplicated throughout the city, such as Lincoln Avenue and Lincoln Place.
The grid system means getting lost in Chicago takes a great deal of effort.
The Encyclopedia of Chicago has more:
The renumbering of Chicago's streets in 1909 and 1911 obviously required a great deal of preparation. Residents needing to notify correspondents of a new house number could find a variety of preprinted postcards in styles ranging from humorous to decorative to matter-of-fact. The August 21, 1909, Record-Herald headlined an article, "Postcard makers Reap Harvest on Change in City's House System."
Besides postcard makers, mapmakers also saw a dramatic rise in business as a result of the new system. This 1910 Rand McNally map shows that every eight blocks on the grid (starting from State Street and moving west) marks a major thoroughfare.
Getting someone's address in Chicago, therefore, becomes just a question of cross-streets. "I'm at 1060 W. Addison," someone says, and all you need to know to get there is, "What hundred north?" (3600, for those unfamiliar with the location.)
In fairness to cities where, for example, West Fourth and West Tenth intersect, Chicago got to start its street system from scratch—twice. Still, it does make living here seem that much more rational.