How important was this 6-foot-deep ditch to the development of Chicago? Its population was less than 5,000 in 1840, at the time the canal was under construction. Just over a decade after the canal opened in 1848, the city’s population burst to more than 100,000, and it nearly tripled again in the following decade. Barges pulled by mule across the divide were laden with so much cargo—grain, lumber, livestock and foodstuffs like fruit, sugar, salt, molasses and whiskey—that Chicago, once a swamp in the middle of the continent, had become the nation’s busiest port by 1869.
