By the Numbers: Irish In America

In honor of St. Patrick’s Day, we take a look at Irish immigration to the United States. Many brought the conflict between Catholics and Protestants with them from the old country. Catholic immigrants also faced a wave of anti-Catholic sentiment in America.


Protestants burned down St. Mary’s Catholic Church in New York City.


A movement known as the Native American Party – and later, the American Party – began winning local and Congressional elections with an anti-Catholic immigration message. They were a semi-secret political party, so a member asked about its activities was supposed to reply, “I know nothing,” which led to the group being called the Know Nothing Party. When it formed as the American Party in 1854, its members called for restrictions on immigration, the exclusion of the foreign-born from voting or holding public office in the United States, and a 21-year residency requirement for citizenship. In the Questions for Admittance to the American Party (1854), inductees committed to “…elect to all offices of Honor, Profit, or Trust, no one but native born citizens of America, of this Country to the exclusion of all Foreigners, and to all Roman Catholics, whether they be of native or Foreign Birth, regardless of all party predilections whatever.” This commitment helped elect American Party governors in Massachusetts and Delaware and placed Millard Fillmore on a presidential ticket in 1856 (he came in a distant third to Democratic winner James Buchanan and Republican John C. Fremont).


Riots between Catholics and Protestants in Philadelphia left 13 dead, prompting New York Archbishop John Hughes to post armed Irishmen at his churches.


Year of the Irish potato blight, which is credited with launching another giant wave of Irish immigration to America.


The year Patrick Kennedy, a farmer from Wexford County, made his way to America. He was the great-great grandfather of President John Fitzgerald Kennedy.


The year Ellis Island opened as an immigrant processing center. Annie Moore, 15, from County Cork, was the first passenger processed.

4.7 million

Population of Ireland in 1891 and 2017.

6.6 million

Population of Ireland in 1851.

8.2 million

Population of Ireland in 1841.

Sources: The Library of Congress,,