Whet Moser argues Chicago’s remarkable growth from frontier town to big city was the result of excrement and new sewers:

The city was literally shaped by excrement. Its biggest single period of growth, the growth that turned Chicago into the Second City by population, came in the late 1800s, when the city’s sewer and sanitary systems were the envy of what were then suburbs. Lake View Township (the whole of the northeast side from North Avenue up to Rogers Park), Hyde Park Township (the south side between Pershing, State, and 138th), Lake Township (the southwest side bordered by Pershing, State, 87th, and Cicero) all latched on to the city when sophisticated sanitary systems were beyond the reach of booming townships, which were tightly restricted by the state’s limits on local debt.

Read on for more of the story of Chicago’s sewers.

This story in Chicago was not wholly unique. The late mid- to late-1800s were a period when numerous suburban communities outside big cities like Chicago, Boston, New York, and Philadelphia were annexed into the city. This annexation was approved by suburban communities for several reasons. First, as Moser notes, sewers and other infrastructure improvements like water and electricity were too expensive for small communities. Second, these communities wanted to be part of the big city and the status that came with that.

Yet, the story changes quite a bit from the 1880s onward when suburban communities started rejecting annexation efforts from big cities. The price of the infrastructure improvements dropped, putting them within reach of smaller suburbs. Cities were growing so fast that they couldn’t keep up with social problems as well as infrastructure improvements, limiting the status appeal of being part of the big city. Finally, an idealism was developing among the suburbs themselves as places people wanted to move to in order to escape the big city. By the 1920s, annexations had basically stopped.

This was a major turning point for most Northeast and Midwest big cities. Once annexations stopped and suburbs decided to go on their own, the boundaries of big cities became fixed. Later, as wealth and jobs fled the city for the suburbs, there were few opportunities for Rust Belt cities to expand their boundaries. In contrast, cities in the South and West (the Sunbelt) have had different annexation histories and many are much bigger in land area.