The parade of kilted Irish-Americans and bagpipers set off on a cold, gray morning. Hundreds of thousands of spectators lined Fifth Avenue, but the shivering, bundled up crowd was only about half as thick as in previous years.
De Blasio held the traditional St. Patrick's Day breakfast at Gracie Mansion with the Irish prime minister, Enda Kenny, but he was boycotting the parade because organizers said marchers were not allowed to carry gay-friendly signs or identify themselves as lesbian, gay, bisexual or transgender.
Police Commissioner William Bratton marched with a contingent of uniformed officers. Gay activists protesting the exclusion of official LGBT groups held a news conference before the march to say they didn't think the NYPD officers should participate in uniform.
"I know that there are thousands and thousands of gay people marching in this parade," said Roman Catholic Cardinal Timothy Dolan, who greeted passing dignitaries in front of St. Patrick's Cathedral and was wearing a woolen Irish cap over his red cardinal's skull cap. "I know it. And I'm glad they are."
Dolan noted that he's not part of the parade leadership and therefore not responsible for who participates, but he said he supports the participation of individual gays. The cardinal declined to comment on the mayor's boycott.
"I'm just hoping this is a day of unity and radiance and joy, I hope, bringing us all together," Dolan said.
Across the Atlantic in the land that inspired St. Patrick's Day, an estimated 400,000 tourists and locals packed the center of Dublin for Ireland's major parade. The hourlong procession featured loads of wit, brightly colored costumes and dancers, including from Ireland's gay community - and nobody had a public word to say about it.
For the second year running, the parade included groups from Ireland's gay rights groups, Dublin Pride and BeLonG To. Gay groups are a big part of the Dublin community dance groups, which wear flamboyant outfits and feature in each year's Dublin parade.
Boston's new mayor, Martin Walsh, opted out of his city's parade Sunday after talks broke down that would have allowed a gay veterans group to march.
Guinness beer abruptly dropped its sponsorship of New York's parade on Sunday over the controversy. The Dublin-based company has pulled sponsorship assets, including on-air presence, parade participation and any promotional materials that weren't already printed, although the beer maker had already made a payment to parade organizers, spokeswoman Alix Dunn said.
Other beer companies earlier joined the boycotts, with Sam Adams withdrawing its sponsorship of Boston's parade and Heineken following suit in New York. That leaves Ford as the last remaining major sponsor of the Manhattan parade.
De Blasio's decision to skip the parade underscores lingering political tensions over gay rights issues in the United States. Kenny, however, refused to be sidelined, saying he'd join the procession Monday in Manhattan because the holiday is about Irishness, not sexuality.
De Blasio, in one of the first major events that Gracie Mansion has hosted under the new mayor, addressed several hundred people at the breakfast, many of Irish descent.
Sporting a green tie, de Blasio, who is not Irish, recalled his roots growing up in Massachusetts, living in congressional district once represented by Irish-Americans John F. Kennedy and Tip O'Neill. "I also grew up in an atmosphere so rich in Irish culture," the mayor said.
He said in a toast that New York is a "city of immigrants" and residents "never forget" where they came from.
Kenny presented de Blasio a book containing a history of Ireland. The mayor of the Big Apple dropped a crystal apple he was presenting to Kenny. It did not appear to break.
Rain didn't stop the huge St. Patrick's Day celebration in Savannah, Ga., though fewer revelers lined Lafayette Square nearing the beginning of the city's parade route. Thinner crowds left plenty of room for umbrellas and party tents as the 190-year-old parade stepped off under rainy skies in Georgia's oldest city.
Kenny, Ireland's head of government, on Sunday became the first Irish prime minister to attend Boston's annual St. Patrick's Day breakfast. He has resisted pressure, in both Ireland and America, to support the gay rights lobby's demand to have equal rights to participate in parades on St. Patrick's Day.
In Ireland, St. Patrick's Day provides the launch of the country's annual push for tourism, a big part of the rural economy. Virtually the entire Irish government left the Emerald Isle for the holiday. Of the government's 28 ministers, 27 are overseas, seeking to boost economic and cultural ties from Beijing to Buenos Aires.
"To Irish people by birth or descent, wherever they may be in the world, and to those who simply consider themselves to be friends of Ireland, I wish each and every one of you a happy, peaceful and authentically Irish St. Patrick's Day," Irish President Michael D. Higgins, the ceremonial head of state and guest of honor at Monday's parade in Dublin, said in a statement.
New York's parade, a tradition that predates the city itself, draws more than 1 million spectators and about 200,000 participants every March 17. It has long been a mandatory stop on the city's political trail, and includes marching bands, traditional Irish dancers and thousands of uniformed city workers.
Associated Press writers Verena Dobnik in New York, Shawn Pogatchnik in Dublin and Russ Bynum in Savannah, Ga., contributed to this report.