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How Tens of Thousands of Irish Immigrants Led the Patriots to Victory During the American Revolution
Soldiers of Irish heritage accounted for up to 50 percent of the Continental Army’s ranks. Driven from their homeland by British oppression, Irish-born rebels also served as spies, politicians and more
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In 1745, a boy named John Barry was born by the sea in southeastern Ireland. He would spend his childhood under England’s thumb. Like other Irish Catholics living in the Protestant kingdom, Barry was prohibited from voting, holding public office or owning a horse that cost more than £5. When he was a teenager, he and his family were forced off their land, reportedly by an English landlord. With few other options, Barry turned his sights toward the sea.
Around 1760, Barry immigrated to Philadelphia, where he pursued a career in shipbuilding and sailing. A decade and a half later, when the Thirteen Colonies revolted against unfair taxes and imperial rule, he became an early patriot, motivated by his experience with British oppression on both sides of the Atlantic.
Barry put this fervor to good use. Appointed a captain in the Continental Navy in 1775, he captured multiple British vessels at the helm of a brigantine called the Lexington. By the American Revolution’s end, he was in command of the Alliance, protecting a cargo ship transporting Cuban gold—seed money for the United States’ national bank. After the war, President George Washington selected Barry as the Navy’s first commissioned officer; today, he’s often described as the “father of the U.S. Navy.”
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When America declared its independence from Britain 250 years ago, on July 4, 1776, a diverse group of patriots joined the fight against the crown. Many were born on American soil. Some came from England or mainland Europe. Still others either emigrated from or traced their ancestry to that small Emerald Isle west of England.
These immigrants’ beef with Britain went deeper than taxes on stamps and tea. The Irish soldiers and sailors who flocked to the patriot cause would prove indispensable to both the defense and the founding of their new country. Despite accounting for just 10 percent of the U.S. population during the war, individuals of Irish heritage represented 25 to 50 percent of the Continental Army.
Few exemplified this dedication to liberty as much as Barry. When a British admiral attempted to persuade the Irish captain to switch sides, he replied, “I have devoted myself to the cause of my adopted country, and not the value or command of the whole British fleet could seduce me from it.”
English rule in Ireland
Ireland is sometimes called England’s “first colony.” During the Iron Age, the island was inhabited by Celts whose ancestors had migrated from mainland Europe. By the fifth century C.E., however, Christian missionaries (including St. Patrick) had arrived on the island to convert its pagan population. In 1171, Henry II of England invaded Ireland, marking the beginning of 800 years of British rule over the island.
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By the dawn of the 17th century, England had devastated Ireland’s ecosystem by cutting down most of the island’s trees as lumber for shipbuilding. James I directed droves of his English and Scottish subjects to move to Ireland, encouraging them to settle on land confiscated from locals. The crown also sent thousands of Irish prisoners to work as indentured servants in British colonies in North America and the Caribbean.
The early modern period ushered in an era of intense religious persecution in Ireland. In the 1530s, England was torn apart by the Reformation, Henry VIII’s forceful, public split with the Catholic Church. The Tudor king rejected the pope’s authority and declared himself head of the Anglican Church. Under Henry’s youngest daughter, Elizabeth I, Parliament outlawed Catholic Mass, preventing much of Ireland’s population from worshipping as they had for centuries. In England itself, Elizabeth ordered the executions of more than 100 Catholic priests on charges of treason.
To punish Catholics perceived as enemies of the state and keep them from rising up against the crown, England enacted the Penal Laws, a series of codes that disenfranchised non-Anglicans in Britain and Ireland. Catholics incurred fines for practicing their religion, and they were barred from teaching and bearing arms, among other restrictions. Designed to be enforced locally, at the discretion of Anglican leaders, the Penal Laws created a culture of division and fear, setting Catholics up for generational poverty.
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“ If you were a member of the Roman Catholic faith, [land] had to be subdivided equally between all male children” upon the landowner’s death, leading to fragmentation of estates over time, says Nathan Mannion, head of exhibitions and programs at Dublin’s Epic the Irish Emigration Museum. (If a landowner had no sons, the estate was divided among his daughters.) “It dilutes the wealth and the position of the families, but it also means it becomes more and more difficult to sustain a family on ever-diminishing plots of land.”
Catholics bore the brunt of religious persecution in Ireland, but the Anglican Church’s ire also extended to Presbyterians, an offshoot Protestant group. This community was mainly based in Ulster, a region in the north of the island. Most Irish Presbyterians were descendants of Scottish immigrants. Although their faith was similar to Anglicanism, their churches were structured differently.
Need to know: Northern Ireland
Unlike Ireland, Northern Ireland is part of the United Kingdom. It was established as a legally distinct entity in 1921, with the partition of Ireland, and comprises six of the nine historical counties of Ulster.If Catholics “were third-class citizens,” Mannion says, “Presbyterians were effectively second-class citizens. Their marriages weren’t recognized. There were fines imposed on those who weren’t in communion with the Anglican faith. If they weren’t attending services, paying tithes, then they were subject to discrimination.”
Irish immigration to America
In the early 18th century, tens of thousands of Irish people, most of them Ulster Presbyterians, decided to leave their homeland in search of a “new life,” says Melanie McComb, a senior genealogist at American Ancestors, a nonprofit family-history organization. Five ships carrying Presbyterian ministers and their congregations sailed to New England in 1718, beginning the so-called Great Migration of the Scots-Irish.
Lured by the promise of greater religious freedom and plentiful land, an estimated 250,000 Scots-Irish had immigrated to the American Colonies by 1775. Catholics also emigrated from Ireland in the pre-Revolutionary period, but they did so in far smaller numbers; as historian Kerby A. Miller writes in Emigrants and Exiles, “Catholics perceived emigration as forced banishment, and most remained at home,” unwilling to relocate to “Protestant-dominated colonies, where they could expect mistreatment and discrimination.”
Given the treatment that these Irish newcomers had endured in the British Isles, it’s perhaps unsurprising that many “threw their lot in with the Continental Army” when the Revolution began, Mannion says. As the 20th-century American theologian Loraine Boettner later wrote, “So intense, universal and aggressive were the Presbyterians in their zeal for liberty that the war was spoken of in England as ‘the Presbyterian Rebellion.’”
Ian Crozier, CEO of the Ulster-Scots Agency, a cultural heritage group based in Northern Ireland, says that Scots-Irish Presbyterians have historically rejected overbearing government control. “Government says, ‘Do this,’ and we go, ‘Is that right?’” Crozier explains. “It’s called thranness,” which translates roughly to “stubborn.”
Irish patriots during the Revolution
So who were these Irish American patriots? They were foot soldiers. They were captains. They were spies. They were printers and designers, delegates to the Continental Congress, and signers of the Declaration of Independence.
After the Continental Congress adopted the Declaration, on July 4, 1776, delegates rushed the text to an Irish-born Philadelphia printer named John Dunlap. (Five years earlier, Dunlap had founded the Pennsylvania Packet, which would become America’s first daily newspaper.) Into the early hours of July 5, Dunlap created 100 to 200 broadsides of the Declaration. Twenty-six of these poster-size prints are known to survive today.
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Eight of the 56 men who signed the Declaration were of Irish descent. Three of them were born in Ireland, including James Smith, whose family had emigrated after enduring exploitation by landlords. As Irish Central noted in 2024, these signers’ “brand of Irish defiance saw right through British imperialism and used Enlightenment republican ideas to create an alternative society for free people.”
During the Revolution, Irish immigrants who enlisted to fight for the Americans were incentivized by both patriotism and the possibility of receiving land as a reward for their service. An Irish politician later reported that “the Irish language was as commonly spoken in the American ranks as English,” adding that Irish valor had “determined the contest.”
County Cork’s Stephen Moylan, a Catholic whose parents had sent him to America to escape religious persecution, commanded a Continental cavalry regiment of light dragoons. Several Irishmen also served as aides-de-camp to Washington. One was John Fitzgerald, born in County Wicklow, and another was James McHenry, a surgeon from County Antrim. Nine of Washington’s generals were born in Ireland, including two major generals and seven brigadier generals.
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Plenty of Irish people fought for the British, too. An estimated one-sixth of Britain’s soldiers were from Ireland, many of them motivated by the promise of regular provisions, cash and pensions, McComb says. But even this group boasted some notable defectors to the patriot cause. One was Thomas Sullivan, a sergeant in the British Army who deserted to serve under patriot Major General Nathanael Greene. In his journal, Sullivan wrote with admiration of the Americans, who “were striving to throw off the yoke under which my native country sunk for many years.”
A few Irish immigrants mastered the risky art of espionage. The tailor Hercules Mulligan— immortalized in the musical Hamilton—was born in Coleraine and immigrated to America as a child. He married the niece of a British naval officer but became a passionate patriot, even joining a volunteer militia. Mulligan’s New York City clothing shop attracted high-status patrons, including loyalists and British officers. At the suggestion of his friend Alexander Hamilton, Mulligan used his business to the Americans’ advantage, coaxing important information out of clients and reporting it to the Continental Army. According to the American Battlefield Trust, Mulligan twice saved Washington “from ruin,” in one instance even foiling an assassination plot against him.
Another Irish spy was Lydia Barrington Darragh, a Quaker woman who’d emigrated from Dublin. In December 1777, during the British occupation of Philadelphia, General William Howe told Darragh that he intended to hold a meeting with his officers in her house. “They wished the family to retire early to bed, adding that when they were going away, they would call her to let them out and extinguish their fire and candles,” journalist Robert Walsh Jr. wrote in an 1827 account. (Mannion, for his part, says, “I’m not sure whether that showed naivety or a level of trust that was definitely unwarranted.”)
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Instead of going to sleep as instructed, Darragh listened in on the meeting through a keyhole, overhearing the British officers’ plans to mount a surprise attack on Washington and his men. She knew “she had to do something with the information, even though her religion forbade getting involved,” biographer Robert N. Fanelli told Smithsonian earlier this year. Ultimately, Darragh conveyed the intelligence to the Continental Army, at great risk to her personal safety.
Near the war’s end, in 1782, Charles Thomson, a native of Londonderry, came up with the final design for the U.S.’s Great Seal in collaboration with a Philadelphia heraldry expert. His biggest contribution was choosing the American bald eagle as the seal’s avian centerpiece. Five years later, four Irish-born men served as delegates to the Constitutional Convention, helping draft the U.S. Constitution. The document was ratified in 1788, cementing the law of the free land.
Inspired by America’s success in liberating itself from English rule, some residents of the Emerald Isle came to view the Revolution as “a template that could be applied to Ireland as well,” Mannion says. “Revolutionary fervor” inspired Irish radicals to imagine an independent republic of their own, the curator adds, and form the Society of United Irishmen in 1791. The group mounted the Irish Rebellion of 1798, fighting back against British rule. The crown crushed the revolt, but the seeds of Irish independence had been sown.
“Irish people in general always root for the underdog,” Mannion says. “We do try to embody that rebel spirit as much as possible.” In the 18th century, he adds, “you have Irish people on both sides of the Atlantic taking part in conflicts to secure independence from a colonial power, and in this case, the same colonial power: Great Britain.”
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