And the victory of President-elect Donald Trump in the Nov. 8 election has raised concerns in Dublin over their future status. Trump signaled his intent to deport millions of illegal immigrants once he takes office, causing ripples of disquiet for tens of thousands of undocumented Irish citizens in so-called sanctuary cities such as Chicago, New York and Boston, where police are not supposed to share information with immigration authorities.
Most have overstayed their visas and entered the casual workforce without the necessary papers. Many were banking on executive orders by President Obama -- now stalled at the Supreme Court -- that would have deferred deportations for millions of illegal immigrants who had employment and family ties in the United States. That plan, under a Trump presidency, looks dead in the water.
“The issue of Irish undocumented has always been a concern, and I think in the light of [Trump's victory] it will continue to be," Ireland's European affairs minister, Dara Murphy, said earlier this week.
He went on: "We have very strong relationships with Irish American politicians in particular, and we will stress the point that these people (illegal Irish immigrants) have made their homes in America and are in many ways American. They want to stay there and contribute to their country and their way of life."
The status of these undocumented Irish workers is an emotive issue at home. Skype phone calls and video conferences for funerals, weddings and other family events are now a familiar phenomenon in parts of Ireland, with relatives in the United States unable to leave out of fear of being barred re-entry.
Anne Anderson, Ireland's ambassador to the United States, told Politico earlier this year that undocumented Irish citizens “are in the shadows but they get on with their daily lives. But of course one of the biggest costs is that they can’t travel back to Ireland.”
Before the U.S. election, Irish Prime Minister Enda Kenny deemed Trump's populist views "racist and dangerous." But he has been more circumspect in the wake of Trump's victory and was one of the first world leaders to speak with the president-elect. Kenny has no plans to meet Trump on a visit to the United States later this month.
Last week, Brendan Howlin, the leader of the social-democratic Labour Party, bemoaned the consequences of Trump's proposals.
"[Trump] said that one cannot obtain legal status or become a citizen of the United States by illegally entering that country,” Howlin said. “He has said that he would deport illegal immigrants from the United States within 100 days of taking office. That clock is ticking."
Irish Sen. Aodhan O'Riordain, another Labour politician, was more blunt with his criticism, denouncing the election of a "fascist" in the United States and arguing that Trump's success brought the world to "an ugly international crossroads." He also worried for the Irish undocumented across the pond.
"There are 50,000 Irish people illegal in America who I'm quite sure are fearful for their futures," O'Riodain said.