17th March is of course St Patrick’s Day with millions of Americans celebrating all things Ireland on Tuesday.
From marching in local parades to putting away more Guinness than they’d care to admit, people mark St Patrick’s Day in all kinds of ways — but Chicago’s tradition is among the most unusual.
Each year, city officials transform the Chicago River by releasing a vivid green dye into the water, starting near the Columbus Drive bridge.
The change happens fast, with the river shifting to a striking shade of green within minutes. It’s at its brightest early on, before the colour gradually fades and the river returns to normal after a few hours.
This year’s dyeing took place on Saturday (14 March), with the colour flowing as far as Orleans Street and stopping just before Wolf Point.
Although the dye is said to be non-toxic, the exact recipe remains closely guarded, known only to the officials responsible for the annual release.
The roots of the tradition go back to the early 1960s, when Mayor Richard J. Daley reportedly floated the idea of turning Lake Michigan green — an effort that was quickly deemed unrealistic.
Instead, inspiration came via a friend of Daley’s who led a local plumbers union. While searching for a leak from a damaged pipe, the team used an orange tracer dye, only to notice it appeared emerald green once it hit the river.
After sharing the discovery with Daley, the two decided the river itself would make the perfect St Patrick’s Day spectacle — and Chicago’s now-famous tradition was born.
The first official dyeing took place in 1962, and it has remained a signature part of the city’s celebrations ever since.
Choose Chicago, a tourist information, said of the event: “The annual Chicago River dyeing is one of the most unique St. Patrick’s Day celebrations in the world. Typically held the Saturday before St. Patrick’s Day (the same day as the downtown parade), this bucket-list event is a beloved tradition that dates back over half a century.
“The brilliant green color only lasts a few hours, so be sure to catch a glimpse and snap some photos before heading off to a local tavern to enjoy some green beer.”
So if you were planning to catch the river in full green on St Patrick’s Day itself, you may have missed your window — the colour only lingers for a short time, as Choose Chicago notes.