It was among Irish American communities that the day became the celebration it is, from its roots as a more solemn day with a religious observance in Ireland.

The spread of St. Patrick’s Day celebrations in the U.S. was a way for Irish immigrant communities, who in the 19th century faced discrimination and opposition, to stake that ground, he says: “It’s a kind of immigrant Irish way of combating nativist antagonism against them.”

Brings Boisterous Parades and Celebrations to New York and Other Cities NEW YORK (AP) — St. Patrick’s Day, the annual celebration of all things Irish, is being marked in cities across the country on Monday with boisterous parades and celebrations.