Which American presidents had Irish roots? More than you'd think.

Ever since John F. Kennedy's trip to Dunganstown, County Wexford, in 1963, almost every President of the United States has traveled across the Atlantic, often to seek out their ancestral home.

With our previous President, Barack Obama, also visiting his ancestral family home, Moneygall, County Offaly, during his time in office, historians began taking a closer look at the 22 American presidents with roots in Ireland.

John Robert Greene, a historian, and author of dozens of books explained: "It's very simple, Catholic votes …There's not a huge love of Irish tradition, with the possible exception of JFK, Reagan, and Bill Clinton, but there's a huge love for Catholic votes and particularly Irish Catholic votes.

Read more: Why hasn’t there been a Catholic President since JFK?

US Presidents with Irish connections 

President Trump does not have Irish roots - his ancestry is German on his father's side and Scottish on his mother's - but he does own a golf course in Ireland, in Doonbeg, Co. Clare. 

Obama and former Taoiseach Enda Kenny. Image: Rolling News.

Obama and former Taoiseach Enda Kenny. Image: Rolling News.

In 1984 President Ronald Regan and his wife Nancy visited Ballyporeen in County Tipperary. Eight bed and breakfasts, two cafes and souvenir businesses opened up. The tourist boom lasted for six or seven years.

The local pub was renamed after the president before he even arrived and after his death in 2005 the Reagan presidential library acquired the interior of the pub. The walls were decked with images of the president around the world.

Ronald Reagan in the Oval Office.

Ronald Reagan in the Oval Office.

The pub's owner, Mary O'Farrell, told the BBC, "He was real Irish in temperament …You'd know he was Irish, he had that sense of humor and glint in his eye."

US Presidents with Irish roots 

Most of the 22 Irish American presidents have their roots in Tyrone and Antrim and come from a Protestant background of 19th century Ulster. They generally settled in the south and west in the US. Later they labeled themselves Scots-Irish in a bid to distinguish themselves from the Catholics fleeing Ireland during the potato famine of the 1840s. It better served those running for the presidency to not associate with those coming out of Ireland, who were being accused of stealing American jobs.

The complete list includes: Andrew Jackson, William Henry Harrison, James Polk, James Buchanan, Abraham Lincoln, Ulysses S. Grant (also the first US president to visit Ireland), Chester Arthur, Grover Cleveland, Benjamin Harrison, William McKinley, Woodrow Wilson, John F. Kennedy, Lyndon B. Johnson, Richard Nixon, Jimmy Carter, Ronald Reagan, George H.W. Bush, Bill Clinton, George W. Bush and Barack Obama. 

During the early 20th century, those attitudes began to change and then along came John F. Kennedy.

Read more: Trump’s Irish golf course shrinks losses, says 2018 was “best year to date”

John F. Kennedy as a Senator.

John F. Kennedy as a Senator.

Although neither his parents or grandparents were born in Ireland, he forged a solid Irish identity and he became the first Catholic to take the office. At Kennedy's rallies, filled with prominent Irish Catholics such as Tip O'Neill, "Danny Boy" was the tune of choice.

Talking about Kennedy Greene said, "He clearly wanted the link to the Irish and he made himself more Irish than any other American president."

Since Kennedy (who was assassinated on November 22, 1963) every president apartment from Gerald Ford has claimed some sort of Irish ancestry, says Greene. Although he commented that in Bill Clinton's case there was no evidence.

Read more: Footage of JFK on his historic trip to Ireland in June 1963

Bill Clinton and former Taoiseach Bertie Ahern. Image: RollingNews.ie.

Bill Clinton and former Taoiseach Bertie Ahern. Image: RollingNews.ie.

US Presidents with Irish connections 

Carl Shanahan, founder of Wild Geese, an organization that promotes Irish culture in the US and worldwide, said that what these presidents are doing is exactly like what millions of Americans do every day.

Shanahan said, "Being Irish doesn't hurt you at any level of society. We were never at war with Americans like the Germans, the Italians, and the Japanese. In Washington's army, the numbers were a third Irish or Scottish-Irish …There is an affinity by association. It's the reputation of the Irish, the Fighting Irish. A guy who gets off his feet and fights the battle and wins. We had boxing champs and baseball teams."

He continues, "We fought their wars, opened up their territories and built their cities. There's nowhere to tell that story and if we don't tell it, then people will forget."

One excellent demonstration of this is the St. Patrick's Day parade, which is older than the United States itself. The first parade took place 250 years ago in 1766, in New York, ten years before the Declaration of Independence.

How are to marking President's Day? Let us know in the comments section, below. 

* Originally published in 2013, updated with recent information in 2018. 

President Ronald Reagan on St. Patrick's Day.