In Times Square, Greg Packer, 39, a highway maintenance worker from Long Island, wore a black t-shirt with "War" written on it to show his support.
"9/11 was the catalyst. Having been in the city on that day, and seeing how the streets were so empty and the sky smelling so bad, it really reminded me that we had to do whatever we had to do," he said. "And tonight is the night."
"I'm representing Ireland and New York today. It's a day for happiness and to be together," said Long Island resident Greg Packer, who sported a bright green wig and a painted green mustache at New York's parade. "It's a day to take in the Irish culture that we have in the city."