Watch Chicago expand through annexation here.

Maps at the Chicago History Museum show that in 1837, city borders were:

• Lake Michigan to the east
• North Avenue to the north
• 22nd Street to the south
• Wood Street to the west

In the Great Fire of 1871, much of the city was destroyed. The most significant annexation in Chicago history came almost two decades later, in 1889.

That’s when Hyde Park, Lake View and Jefferson and Lake townships became part of Chicago. The annexations were the result of an election and added 125 miles and 225,000 people to the city, making it the nation’s largest city by square mileage at the time…

“One of the reasons annexation stops […] in the early 1900s is because the city really doesn’t want to annex any more territory,” said Chicago historian Ann Keating, who wrote Chicago Neighborhoods and Suburbs: A Historical Guide and co-edited The Encyclopedia of Chicago. “Our vision is suburban communities wouldn’t want to join in to the city, but the fact of the matter is the city kind of hits a point where they can no longer extend services.”

This is a common trait of most American big cities: they started relatively small and then annexed quite a bit of territory. However, Chicago’s experience mirrors cities in the North which essentially couldn’t annex much past 1900. While suburbs prior to this point had been willing to join the city to gain from the big city’s services and the city’s prestige, by around 1900 these local services were cheaper to build themselves and cities had different reputations. But, annexation was still quite common for Sunbelt cities, most of whom were able to continue to annex through the 20th century. David Rusk tracks these annexations in his book Cities Without Suburbs. Here is one chart:

Quite a big difference which Rusk argues allowed Sunbelt cities to capture more of the suburban growth and benefit from a wider tax base and more diverse population.