Some say that on March 17, St. Patrick's Day, everyone is Irish. Well, here in America, we may not all be Irish, but a lot of us are. About 34.5 million residents claim Irish ancestry - that's almost nine times the entire population of Ireland (4.1 million). Irish is also the nation's second most frequently reported ancestry. According to American FactFinder, Irish ancestry trails only German ancestry, and is actually the leading ancestry group in Delaware, Massachusetts and New Hampshire.

More Interesting Irish-American Facts:

The Mother Tongue
According to the U.S. Census, there are 25,870 U.S. residents who speak Irish Gaelic at home.

Coming to America
There have been more than 4.8 million immigrants from Ireland lawfully admitted to the United States since 1820, the earliest year for which official immigration records exist. Almost half of them came to America prior to 1870. They are still coming, however. About 128,000 current U.S. residents were born in Ireland and millions more had parents or grandparents born on the Emerald Isle, including President John Fitzgerald Kennedy and the rest of the Kennedy Clan.

Related:
Tracing Your Irish Family Tree
Common Surnames of Ireland & Their Meanings