How Chicago Got Its Odd Shape

Looking at a map of Chicago can produce mixed reactions. On the one hand, there’s an orderly grid of streets of equal length, a river dividing the city into the North, South, and West Sides, and a few interstate highways that bring commuters in from the suburbs. But on the other, its boundaries—with the exception of Lake Michigan to the east—make it possible to pass in and out of the city limits while remaining on the same road. Plus, there are two villages surrounded by Chicago, as well as a narrow strip of one street that connects the city to one of its most important assets. Here’s how those 234 square miles came to be.

By Dave Lifton (@daveeatschicago)

For the purposes of clarity, municipalities, neighborhoods, and streets will be referred to by their current names.

It started simply enough, with James Thompson’s 1830 plat of the as-yet unincorporated Town of Chicago. At less than half a square mile, it consisted of 58 blocks, with Kinzie (north), Jefferson (west), Madison (south), and State (east) as the borders. Everything east of State south of the river belonged to the federal government as part of Fort Dearborn.

Expansions began almost immediately, with new boundaries drawn in 1833 (Chicago’s founding as a town) and 1835. The decommissioning of the fort in 1836 ceded that eastern land to Chicago, and when it was incorporated as a City on March 4^th, 1837, the boundaries were Cermak (south), Wood (west) and North (north), with everything east of La Salle going up a half-mile to Armitage, bringing the total to 10 square miles.

This remained the City of Chicago throughout the 1840s, but that would soon change, as the city annexed adjacent land. It pushed north to Fullerton and west to Western in 1851, south to Pershing in 1863, and further westward to Pulaski in 1869. It’s interesting to note that the South and West Sides were expanding faster than the North Side, with immigrants from across Europe landing in Chicago to work in factories and the Union Stock Yards. From 1850-1870, the population increased tenfold, from 30,000 to 300,000.

Two years later, the Great Chicago Fire wiped out downtown and almost the entire North Side. By then, all of Cook County had been divided into villages, townships, and cities. But Chicago, as the largest and wealthiest thanks to the river and the growing railroad industry, was able to deliver services more effectively than its neighbors, and at a lower cost to taxpayers. For example, it had already developed the country’s first underground sewers by raising the streets and built a system to draw in fresh water from two miles out on Lake Michigan.

With residents of those suburbs wanting better sanitation and other services, four adjacent municipalities—the City of Lake View, Jefferson Township, Village of Hyde Park, and Lake Township—as well as a part of Cicero voted to become part of Chicago. In a vote on June 29^th, 1889, the annexation was approved. Chicago quadrupled in size, from 44 to 169 square miles, and the population went from 900,000 to 1.1 million, passing Philadelphia as the second largest city in the U.S.

The northern border (Devon) was simple, but the rest was more confusing. Jefferson Township extended as far west as Harlem, but Lake Township ended at Cicero, with a southern border at 87^th. Hyde Park went all the way down to 138^th and the border with Indiana, with State at its westernmost point.

But the city wasn’t done. Within two years, the South Side added another 10 square miles below 87^th. In 1893, the annexation of Rogers Park and West Ridge set the northeastern border at Howard, and Austin joined as the 19^th century drew to a close.

Between 1910 and 1930, the rest of the current map was added in bits and pieces on the South and Northwest Sides, including Edison Park, Beverly, Morgan Park, and Mt. Greenwood. But some immediate municipalities—including Oak Park, Evanston, Skokie, Cicero, and Blue Island—had no interest in being absorbed into Chicago.

After World War II, Chicago acquired federal land to build O’Hare International Airport, but it was outside the city limits. Park Ridge, Des Plaines, Norridge, and Harwood Heights had long been against annexation, so it worked around the latter two, picking of sections of land, including a segment of the Cook County Forest Preserve.

Lastly, to connect the airport to the rest of the city, Mayor Richard J. Daley made a deal in 1961 with Rosemont to acquire a small section of Foster to connect the airport to the rest of Chicago. Norridge and Harwood Heights are therefore located within the borders of the larger city, but are independent entities.

And none of this includes the numerous public works projects over the decades that have filled in the lake to create Chicago’s famous lakefront, including its beaches, Navy Pier, Lake Shore Drive, and the Museum Campus.