Hundreds of thousands of people lined the 42-block parade route, which takes marchers past St. Patrick's Cathedral up to 86th Street. Mayor Michael Bloomberg and Police Commissioner Raymond Kelly led the bagpipers up toward Central Park, where revelers waved Irish flags and cheered as soldiers and police officers passed.
"The luck of the Irish means that if you are Irish, you're lucky enough," Bloomberg told reporters.
The onlookers - wearing green and orange face paint and all manner of shamrock-themed apparel - came from all over the world. Nancy Felton, of Monticello, Iowa, was checking the parade off her bucket list of things she wants to do before she dies.
"The parades we usually see in Iowa are only half an hour," she said. "But this one's supposed to be three hours. So we can't wait."
This year's grand marshal is Francis X. Comerford, an executive with NBC. He grew up in Brooklyn but traces his Irish lineage back to Ireland's County Kilkenny.
Before the parade stepped off Saturday, the leader of New York City's Roman Catholics announced that St. Patrick's Cathedral would be undergoing a $175 million renovation.
Cardinal Timothy Dolan said the first phase will involve cleaning the cathedral's soot-damaged exterior and replacing its windows.
"It really wasn't a choice for us," Dolan said. "It's a necessity, not a luxury. We're getting buckets of stones every day that fall from the cathedral."
Bronagh Premaillon lives in Paris but grew up in Ireland. She was celebrating her 60th birthday at the parade.
"I find it very much like Ireland here," she said. "Everybody's dressed in green. I think it's a very exciting moment for the Irish people."
Associated Press Radio Correspondent Julie Walker contributed to this report.
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