The "Little Italies" in which Italians settled were a series of densely populated communities of tenements, pushcarts, and street vendors that dotted the city's boroughs. Immigrants from particular regions of Italy tended to settle in the same neighborhoods of New York, often on the same streets. Traditions of close living in southern Italian towns had long encouraged intense sociability, and now they crowded into cold, inhospitable tenements and began earning a living for themselves while giving shape to new and original forms of community life.

A host of institutions soon began to appear in the Little Italies. Italians started mutual aid societies, clubs, and civic associations such as the Sons of Italy, founded in 1905. The Tiro a Segno Club, started in 1882, remains the oldest private association of Italian professionals in the city. An Italian Chamber of Commerce opened in Manhattan in 1887, and the Columbus Hospital, founded by Mother Cabrini's Sisters of the Sacred Heart, began operations in 1892.

In lower Manhattan's Mulberry Bend area and in East Harlem, Italians built churches and organized religious festivals. The Church of Our Lady of Loreto, opened in 1892 on Elizabeth Street, was one of the earliest Italian parishes designed to serve the new immigrants. Mulberry Street's Neapolitan Feast of San Gennaro and Astoria's Feast of the Lilies are still celebrated today.

As the number of Italians grew, Little Italies developed in Staten Island and Brooklyn, and with the growth of subway lines to the outer boroughs similar communities appeared in Queens and the Bronx.