Pennsylvania’s deep and lasting connection with Ireland stretches back to the 17th century, shaping the state’s history through waves of immigration, political involvement, business, and cultural life.
The first major group of Irish immigrants to Pennsylvania were the Scots-Irish, or Ulster-Scots—Presbyterians who fled religious persecution in Ireland. Welcomed by William Penn’s “oasis of religious tolerance,” they arrived in two major waves: from 1701 to 1776 and again between 1780 and 1820. They were soon followed by Catholic Irish immigrants, particularly after the devastating Great Famine of the 1840s.
Philadelphia became a key port of entry and the center of Presbyterianism in America. The Scots-Irish spread into the hinterlands of Virginia, the Carolinas, Kentucky, and Tennessee, often romanticized as pioneers pushing through the Cumberland Gap. By 1790, Scots-Irish accounted for a quarter of Philadelphia’s population and 15% statewide.
Their political contributions were also significant. Of the 56 signers of the Declaration of Independence, nine were Irish, five of Scots-Irish descent. Notably, George Taylor and James Smith represented Pennsylvania. Thomas McKean, born in Ulster, became an active patriot and later Governor of Pennsylvania.
Over time, Irish Americans—both Scots-Irish and Catholic—helped shape Pennsylvania’s economy. The Mellon family, originally from County Tyrone, became titans of banking, oil, and philanthropy. Irish laborers contributed to monumental projects like the Philadelphia-Pittsburgh Canal, the Pennsylvania Railroad, and the state’s mines and oilfields.
The Catholic Irish, despite initial discrimination and riots in the 1840s, established themselves politically and socially, particularly in advocating for Irish independence. Their resolve was also demonstrated during the Civil War, most famously by the Irish Brigade at Gettysburg, where the 69th Pennsylvania Irish Volunteers played a key role in repelling Pickett’s Charge.
Cultural contributions followed. Film star Grace Kelly’s family made their fortune in Philadelphia construction. Connie Mack (Cornelius McGillicuddy), a baseball legend, managed the Philadelphia Athletics for five decades, winning five World Series.
Villanova University became a beacon for Irish athletes, producing Olympic champions like Ronnie Delany and Eamonn Coghlan. Other universities like St. Joseph’s and LaSalle educated generations of Irish Americans.
The state’s Ulster heritage lives on in Pennsylvania town names such as Derry, Londonderry, Armagh, and Newry. Irish-American politicians continue to serve at all levels of government, while celebrities like Kevin Bacon and Bradley Cooper trace their roots back to Ireland.
Modern ties remain strong. Pittsburgh Steelers owner Dan Rooney served as U.S. ambassador to Ireland in 2009, further cementing cultural connections.
Though national narratives often focus on New York, Boston, and Chicago, Pennsylvania’s Irish legacy is equally profound. The state provided opportunity and security; the Irish, in turn, contributed resilience, labor, and leadership.
As political and social events in Pennsylvania draw worldwide attention, from elections to acts of political violence, they resonate not only across America but also in Dublin and Belfast—testimony to a bond that has endured for centuries and shows no sign of weakening.
Paul McElhinney is a writer based in Wexford, Ireland. His work focuses on politics, history, culture, and sport. He is the author of "Lion of the RAF," a biography of Air Marshal Sir George Beamish, and has contributed to several Irish, British, and American publications. He has researched the influence of the Scots-Irish and Catholic Irish in the state of Pennsylvania since William Penn in the 17th century and up to the present day.
Totally misleading article. There were not nine Irish who signed the declaration of Independence. Totally false information. The Ulster Scots were not Irish. Ever. Do not refer to them as Irish Americans. Nothing Irish about them. They were British, by language, religion & culture. According to the 2021 census in the North of Ireland the majority still identify as British only. Do you call european descent citizens of the US native Americans? Of course you don’t. That articles such as this infer that there was some sort of common connection between Scots settlers in Ireland & the Irish which was… Read more »
Mr. Elliott. Anyone who comes from Ulster and has lived there for a couple of generations or more is Irish in my book- and in the estimation of most Irish people. You draw a rigid definition of who is entitled to be Irish or not. Of course, the Ulster Scots had British antecedents but this did not negate their Irishness. Their distinctions from and differences with those of Irish Catholic and nationalist backgrounds do not in any way, negate that fact. Is the American nature of hyphenated Americans diluted by reference to their immigrant backgrounds? That is not the American… Read more »