On this day in 1908, Chicago’s Board of Aldermen announce that the addresses in Chicago will all be changed beginning September 1st, 1909. Madison and State streets are declared the center of the grid system, and all addresses will be based on their proximity to those streets. (Photo: Madison & State Street in 1908) The city is divided into one-mile sections which contain 8 blocks to the mile. Every average block is assigned a new series of 100 numbers. Therefore, each 800 in numbers is one mile.
The streets are numbered going south, and named going north, and an alphabetical system is used. That’s why all of the streets with the same letters are lumped together. Every four blocks (or half mile) is a major secondary street (like Addison is 3600, Irving Park Rd. is 4000, etc.) Thanks to this system, Chicago is still one of the most easily navigable major cities in the world.
