Final answer:
The river dyed green for St. Patrick's Day is in Chicago, Illinois. This longstanding tradition is a hallmark of the city's festivities, which also include a grand parade that showcases Chicago's rich Irish-American heritage.
Step-by-step explanation:
The river that is dyed green to honor Saint Patrick's Day is located in the city of Chicago, Illinois. This unique tradition started over half a century ago, and it is a significant part of the city's annual St. Patrick's Day celebration. Large crowds, including both people of Irish heritage and those simply joining in the festivities, come together clad in green to watch the Chicago River be transformed into a vibrant green waterway. The dyeing of the river is one of the most visually striking ways that Chicago marks the occasion, blending ethnic pride with a citywide celebration.
Alongside the river dyeing, the city hosts an expansive St. Patrick's Day parade, which is a testament to the rich Irish-American history in Chicago. This parade reflects the city's cultural diversity, as it intertwines ethnic, religious, and civic elements into one grand public event. The dyeing of the Chicago River is a beloved spectacle that captures the spirit of Patrick's Day, attracting both locals and tourists to participate in the revelry that has become a significant part of Chicago's cultural landscape.