NEW YORK — St. Patrick’s Day celebrations across the country are back after a two-year hiatus, including the nation’s largest in New York City, in a sign of growing hope that the worst of the coronavirus pandemic may be over.

The holiday served as a key marker in the outbreak’s progression, with parades celebrating Irish heritage among the first big public events to be called off in 2020. An ominous acceleration in infections quickly cascaded into broad shutdowns.

The full-fledged return of New York’s parade on Thursday coincides with the city’s wider reopening. Major mask and vaccination rules were recently lifted.

“Psychologically, it means a lot,” said Sean Lane, the chair of the parade’s organizing group. “New York really needs this.”

The city’s entertainment and nightlife scenes have particularly welcomed the return to a normal St. Patrick’s Day party.

“This is the best thing that happened to us in two years,” said Mike Carty, the Ireland-born owner of Rosie O’Grady’s, a restaurant and pub in the Theater District.

“We need the business, and this really kicked it off,” said Carty, who will be hosting the parade’s grand marshal after the procession.

Celebrations are back in other cities, too.

Over the weekend, Chicago dyed its river green, after doing so without much fanfare last year and skipping the tradition altogether during the initial virus onslaught.

Boston, home to one of the country’s largest Irish enclaves, is resuming its annual parade Sunday after a two-year absence. So is Savannah, Georgia, where the parade’s cancellation disrupted a nearly two-century tradition.

Some communities in Florida, one of the first states to reopen its economy, were also bringing their parades back.

Florida Gov. Ron DeSantis chose St. Patrick’s Day two years ago to shutter restaurants, bars and nightclubs — a dramatic move by the Republican and which underscored the fear and uncertainty of the time.

Since then, DeSantis has been one of the country’s leading voices against mask and vaccine mandates, as well as other pandemic measures.

New York’s parade — the largest and oldest of them all, first held in 1762 — starts at 11 a.m. and runs 35 blocks along Fifth Avenue, past St. Patrick’s Cathedral and Central Park.

It’s being held as the city emerges from a discouraging bout with the highly contagious omicron variant, which killed more than 4,000 people in New York City in January and February.

New infections and hospitalizations have declined since the surge, prompting city officials to green-light the procession.

On the eve of the holiday, Mayor Eric Adams raised the Irish flag at a park located on the southern tip of Manhattan, not far from Ellis Island, to honor the city’s Irish history.

“This St. Patrick’s Day, we honor those Irish immigrants who relocated and helped build our city, and the many Irish Americans who serve New York City to this day,” the mayor said. “Today, we celebrate the fighting spirit of the Irish with the courage and resilience of this entire city.”

Currently, you don’t need to show proof of vaccination to dine indoors at a restaurant in New York, but huge numbers of people still wear masks in public and avoid big crowds. Office towers remain partially empty, as many businesses still haven’t called employees back to their cubicles. Tourists, once thick enough to obstruct Manhattan sidewalks, are still not back in their usual numbers.

“If you walk around the city, it’s still very different,” said Lane, the parade organizer and a financial adviser at a major Wall Street firm. “It’s a very different vibe when you walk in Manhattan versus what it would have been two years ago, because the people aren’t fully back yet.”

Allowing the parade to proceed, he said, could provide a surge of confidence among New Yorkers to return to public life.

This year’s parade is two years in the making, after token processions during the pandemic.

To keep the tradition going, organizers in 2020 and 2021 quietly held small parades on St. Patrick’s Day, right around sunrise, when the streets were empty. Bagpipes accompanied a tiny contingent of officials and a smattering of people drawn by the music.

It remains to be seen if big crowds will show up for this year’s parade, although organizers expect hordes — even if many New Yorkers remain skittish about massive, potentially virus-spreading public events.

Organizers hope people will turn out not just to commemorate the holiday, but to honor the first responders who helped the city get through the pandemic, as well as in support of a delegation of Ukrainian marchers bringing attention to the war in their homeland.