Stock Photo: Bagpiper and Drummer representing the Knights of Columbus marching in St. Patrick's Day Parade, Park Slope, Brooklyn, New York. The Irish community is one of New York's major and important ethnic groups, and has been a significant proportion of the city's population since the waves of immigration in the late 1800s and New York City today has the largest number of Irish-Americans of any city in America. Parades are an important part of Irish culture..