Groundhog Day is behind us. Easter is around the corner. And in the middle is a holiday associated with merry drinking and a centuries-old religious figure: St. Patrick’s Day.

Monday, March 17, is the holiday to celebrate everything Irish, including St. Patrick, the patron saint of Ireland.

Cities across the U.S. will celebrate with parades of green adornment, Irish foods and thematic bar crawls.

But St. Patrick’s Day wasn’t always a day for partying. Here is what you need to know about the day to celebrate Irish heritage.

St. Patrick’s Day 2025: Save some green with these food and drink freebies, deals

Who was St. Patrick?

St. Patrick is credited with introducing Christianity to Ireland in the 5th century.

But the man who spurred an Irish holiday wasn’t Irish himself. He was born in Roman Britain, kidnapped and brought to Ireland as a slave at 16, according to the History Channel. Patrick escaped slavery but returned to Ireland later.

Why do we celebrate St. Patrick’s Day on March 17?

Legend has it that Patrick died on March 17.

People in Ireland started observing a feast day on March 17 in celebration around the ninth or 10th century, according to the History Channel, but the parades to honor it actually started in America.

The official New York City parade dates to March 17, 1766, according to the Library of Congress.

St. Patrick’s Day was once a solemn religious holiday

Irish culture and heritage experts previously have told USA TODAY the holiday was once a solemn religious day, but it started getting its boozy reputation when the Americans started celebrating it.

Although it is not a federal holiday in the U.S., it is a bank holiday and a great source of pride in Ireland. Leaders also use the day to promote Irish partnerships abroad across various industries.

Irish people in America by the numbers

Many Americans have something to celebrate this St. Patrick’s Day, according to a news release from the U.S. Census Bureau:

• 30.5 million U.S. residents claimed Irish ancestry in 2023.
• Cook County, Illinois, which includes Chicago, is the U.S. county with the largest Irish-American population, according to 2023 data. The population comes in at 434,081.
• 117,219 U.S. residents were born in Ireland, as of 2023.

Kinsey Crowley is a trending news reporter at USA TODAY. Reach her at [email protected], and follow her on X and TikTok @kinseycrowley.

(This article was updated to include video.)