Joe Biden will become the eighth sitting US president to visit Ireland this week.
He will arrive in Belfast tonight ahead of a three-day visit to the island.
Many of his predecessors have also sought out their Irish roots, sometimes to be greeted by cheering crowds, and occasionally by protests.
John F Kennedy, June 1963
President John F Kennedy came to Ireland five months before his assassination for a visit that drew huge crowds wherever he travelled.
He later told aides that it was the best four days of his life, according to the book "JFK in Ireland".
President Kennedy became the first foreign leader to address a joint sitting of the houses of parliament, and his speech also marked the first time cameras were allowed into the chamber to record proceedings.
All eight of the president's great-grandparents migrated to Boston from Ireland during the Great Famine of the late 1840s.
"It took 115 years to make this trip, and 6,000 miles, and three generations," Mr Kennedy, the United States' first Irish-Catholic president, said in a speech by the River Barrow near one of his ancestral homes in Co Wexford.
Richard Nixon, October 1970
President Richard Nixon's state trip to Ireland during the early part of his presidency included a visit to a Quaker burial ground in Co Kildare, where his mother's ancestors are buried.
The visit was marred by some protests against the Vietnam War.
One man threw eggs at the presidential motorcade as it passed through Dublin city centre, forcing a waving Mr Nixon back inside the car for cover.
More demonstrators awaited the president outside Dublin Castle, where he and first lady Pat Nixon met taoiseach Jack Lynch for lunch.
Ronald Reagan, June 1984
Ronald Reagan's visit to Ireland was memorable for a photograph of the president drinking a pint in John O'Farrell's pub in Ballyporeen, Co Tipperary, where his great-grandfather Michael Regan was born in 1829.
Renamed 'The Ronald Reagan' for the visit, the entire interior of the pub - including the counter, the wall-length display cabinet and the beer taps - was transported to The Ronald Reagan Presidential Library in California in 2004.
Bill Clinton, 1995, 1998 and 2000
President Clinton visited Ireland and Northern Ireland three times, with the first trip, in November 1995, timed to support progress towards a peace deal that his administration would help broker over the following two-and-a-half years
Crowds lined the streets in both Belfast and Derry to see him.
In Belfast, an estimated 50,000 people from both sides of the sectarian divide watched him deliver a strong message for peace.
Huge crowds also turned out for an address in Dublin.
He returned in September 1998 after majorities on both sides of the border backed the Good Friday Agreement, and again in December 2000 to break a political deadlock as all sides struggled to implement parts of the peace accord.
George W Bush, 2003, 2004 and 2008
Some 10,000 people turned out for a 'Stop Bush' rally in Dublin in June 2004, while the president was in the south of the country for an EU-US summit held during Ireland's six-month presidency of the European Union.
The president also visited Northern Ireland in 2003, shortly after the power-sharing government formed as part of the peace deal collapsed, and returned in 2008 after the devolved institutions were restored.
Barack Obama, May 2011
Barack Obama celebrated his Irish roots with a visit to the village of Moneygall, Co Offaly, the birthplace of his great-great-great grandfather, who left for New York more than 150 years earlier.
He met members of the public and drank a pint of Guinness in the local pub before delivering a 20-minute speech to a jubilant crowd of around 25,000 in central Dublin, declaring solidarity between the US and then economically struggling Ireland.
"I'm Barack Obama, from the Moneygall Obamas. And I've come home to find the apostrophe that we lost somewhere along the way," he said.
The president visited Belfast two years later while in Northern Ireland for a G8 summit.
Donald Trump, June 2019
After being feted by Britain's Queen Elizabeth and other members of the royal family on a state visit to the UK, Donald Trump spent a low-key two days in Ireland, almost entirely at his golf resort in Co Clare.
While Mr Trump made no appearances open to the Irish public and met Taoiseach Leo Varadkar only in the airport on his arrival, his sons Eric and Donald Junior toured the pubs in the village of Doonbeg beside the resort, buying drinks for locals.
