The growth of the built-up area of metropolitan Chicago can be summarized in three phases. Before 1900, streetcars and commuter railroad service conspired to create a fairly compact city together with small clusters of development around outlying railroad stations. Several outlying satellite cities, such as Joliet and Elgin, studded the hinterland. By 1955, the railroad suburbs had proliferated and matured, creating a massive star-shaped metropolitan geometry, while widespread automobile ownership had encouraged the extension of the continuously built-up zone around the urban core. After 1955, construction of the expressway system permitted a vast decentralization of population and activity that filled in many of the interstices between the railroad axes radiating from the central city, producing a more rounded overall geometry. By the end of the twentieth century, there was hardly a farmer's field to be seen within forty miles of the city center in any direction.

Author: Michael P. Conzen (Research assistance: Dennis McClendon)
Source: Newberry Library