5 Chicago River Facts That Will Blow Your Mind
You've walked along it. You've crossed it a hundred times. You've taken the architecture tour and looked up at the buildings from a boat. But the Chicago River has a history so wild, so audacious, and so uniquely American that most people who live here don't know half of it. Here are five facts about the Chicago River that will completely change how you see it.
1. They Literally Reversed the Flow of the River — and It Worked
This is the one that stops people cold. In 1900, the city of Chicago reversed the flow of the Chicago River. Not diverted it slightly. Reversed it entirely — making it flow away from Lake Michigan instead of into it.
Why? Because the river had become so polluted with sewage that it was contaminating the city's drinking water supply from the lake, and people were dying from typhoid and cholera at catastrophic rates. The solution was the Chicago Sanitary and Ship Canal, one of the greatest engineering projects in American history — a 28-mile canal that changed the direction of an entire river and redirected Chicago's waste toward the Mississippi River instead of Lake Michigan.
When the reversal happened, downstream communities were furious. St. Louis threatened to sue. None of it stopped Chicago. The river was reversed. The city's water got clean. That's Chicago energy in its purest form.
2. The River Was Dyed Green for St. Patrick's Day Starting in 1962 — By Accident
The Chicago River turns bright green every St. Patrick's Day, and it's one of the most iconic traditions in the city. But the tradition started almost by accident. In 1962, Stephen Bailey — a business manager for the Chicago Journeymen Plumbers union — noticed that a plumber's coveralls were stained green from dye used to detect illegal sewage dumping in the river. He had the idea to use the same dye to color the whole river green for the parade.
The first attempt used 100 pounds of dye and turned the river green for a week. That was too much. They've since refined it to about 40 pounds of an environmentally safe dye that fades within a few hours. The formula for the exact dye used is a closely guarded secret held by a small group of plumbers. Chicagoans have been showing up to watch the river turn green every March ever since.
3. The River Has Three Branches — Most People Only Know One
When most people think of the Chicago River they think of the main branch running through downtown — the one with the Riverwalk, the architecture tour boats, and the bridges. But the river actually has three branches forming a Y-shape through the city.
The North Branch runs up through Lincoln Park, Ravenswood, and into the North Shore suburbs. The South Branch — which is where Neon Paddle launches its tours from Ping Tom Park in Chinatown — runs through the Near South Side and connects to the Sanitary and Ship Canal. The South Branch offers some of the most dramatic views of the downtown skyline precisely because of the distance and angle — you can see the full height and spread of the city in a way the main branch doesn't allow.
Most Chicagoans have spent years on the main branch without ever experiencing the South Branch. It's the river's best kept secret.
4. Chicago Has More Moveable Bridges Than Any City in the World
Chicago has 37 moveable bridges spanning the Chicago River — more than any other city on earth. Most of them are bascule bridges, which means they operate like a seesaw, with a counterweight lifting one end while the other rises to let boats through. The mechanism was pioneered in Chicago and became the standard for moveable bridge construction worldwide.
When you're on the water and you glide under one of these bridges, you're passing under more than a century of engineering history. The bridges were built for a city that understood from the beginning that the river was a working waterway and that ships and people needed to coexist. That tension — between commerce and community, movement and stillness — is still part of the river's character today.
The River Inspired One of the Most Influential Urban Planning Documents in History
In 1909, architect Daniel Burnham and his collaborator Edward Bennett published the Plan of Chicago — a comprehensive vision for the city's development that influenced urban planning around the world. One of its central principles was that the lakefront and riverfront should remain public and accessible to all citizens, regardless of income or neighborhood.
That principle is why Chicago's lakefront has no private development on it. That principle is why the Riverwalk exists. That principle is why Ping Tom Memorial Park, where Neon Paddle launches its tours, is a public green space on the river in Chinatown rather than a condo development.
The river you float on today was protected over a century ago by people who understood that water belongs to the city and its people. Getting on it feels different when you know that.