Chicago is the U.S. city famous for dyeing its river green, specifically the Chicago River, as part of its St. Patrick’s Day celebrations.

Quick Scoop

  • The Chicago River has been dyed bright green every year around St. Patrick’s Day since the early 1960s.
  • The tradition started when city leaders and the local plumbers’ union used tracing dye and realized it could turn the river a vivid emerald color for the holiday.
  • Today an environmentally friendly, vegetable-based powder is used, and a short stretch of the downtown river is turned green for just a few hours during the festivities.

The iconic green river has become one of Chicago’s most recognizable St. Patrick’s Day images and has inspired other cities to color their waterways, even though Chicago remains the best-known for the practice.

TL;DR: The US city that dyes its river green is Chicago, and the river is the Chicago River, done each year for St. Patrick’s Day with a special, temporary dye.

Information gathered from public forums or data available on the internet and portrayed here.