It has been estimated that one out of every two Americans living today can trace his or her family history back to at least one ancestor who passed through the famous immigration station on New York's Ellis Island.³³

On its busiest day—April 17th, 1907—the Ellis Island immigration station processed the arrivals of 11,747 European newcomers.³⁴

Contrary to popular mythology, a huge percentage of European immigrants to the United States never dreamt of settling permanently on these shores, but rather hoped only to earn enough money in America to return prosperously to their home countries. In the late-19th and early-20th centuries, nearly half of all European immigrants eventually repatriated to their homelands. Among major immigrant groups, only Irish Catholics and Eastern European Jews—both groups that endured grave repression or poverty in the Old World—did not repatriate in large numbers.³⁵

In 1903, New York City inspectors counted more than 2,200 immigrants living in the overcrowded tenements of a single city block of the Lower East Side. That block—bounded by Orchard, Allen, Delancey, and Broome Streets—may have been the most densely populated location on Earth. If all of New York had been settled so densely, the entire population of the United States at the time could have been packed within the city limits.³⁶

The invention of the steamship greatly facilitated the immigration boom of the late-19th century. In 1856, 96% of immigrants to New York arrived by sailing vessel, having endured transatlantic journeys that could last as long as three months. By 1873, 98% arrived by steamship, which reduced travel time to just ten days.³⁷