The Kennedy political dynasty can trave its Irish roots to Dunganstown in Wexford.

The story of the Kennedy family is of course the classic Irish-American immigrant tale – if not indeed the classic American immigrant tale.
JFK’s visit to Ireland as president in June 1963 was a famous moment in Irish history. While there, he visited Dunganstown, to see the family farm and visit relatives. He also saw the docks of the town of New Ross, from where his great-grandfather boarded a ship called the Washington Irving for the New World.
Speaking at a ceremony in New Ross, JFK paid tribute to his Irish heritage. “When my great grandfather left here to become a cooper in East Boston, he carried nothing with him except two things: a strong religious faith and a strong desire for liberty. I am glad to say that all his grandchildren have valued that inheritance.”
Historian Jay P. Dolan, who was working as an advisor to Kennedy at the time said that the president was “getting so Irish, the next thing you know he’ll be speaking with a brogue." JFK later said that the Irish trip was “one of the most moving experiences” of his life.
Poignantly, JFK promised an audience in Limerick that he would return in the springtime. He said Ireland “is not the land of my birth, but it the land for which I hold the greatest affection, and I will certainly come back in the springtime.”
Robert Kennedy
Senator Robert R Kennedy represented New York from 1965 until June 1968 when he was shot and killed in California while campaigning for the Democratic presidential nomination.
The U.S attorney general from 1961-64, an a Senator for New York from 1965 until 1968, Robert was also one of JFK’s closest advisors. This was illustrated in the Kevin Cosner movie about the Cuban Missile crisis, “Thirteen Days.”
After his brother’s assassination, he continued as attorney general for another nine months, resigning after he won the Senate seat for New York.  He and President Lyndon Johnson later clashed over a number of issues, the most important of which was the Vietnam War.
Robert main rival for the Democratic Party nomination was Eugene McCarthy, who he beat in the vitally important California primary on June 5, 1968. But shortly after midnight on June 6,  a 24-year-old Palestinian called Sirhan Sirhan shot Kennedy Robert died later that day. 
His brother Edward, who delivered Robert’s eulogy, quoted his brother's paraphrasing of a quote from the famous Irish playwright, George Bernard Shaw. "Some men see things as they are and say 'Why?' I dream things that never were and say, 'Why not?'"
Edward Kennedy
As one of the original Four Horsemen who formed the Friends of Ireland group, along with Tip O'Neill, Patrick Moynihan and Governor Hugh Carey of New York, Senator Kennedy championed the cause of the International Fund for Ireland, an annual appropriation of U.S. funds to benefit disadvantaged areas.
In more recent years, he has spearheaded the push for immigration reform. Kennedy's support for constitutional nationalism in Ireland has long been evident through his friendship with the legendary John Hume, former leader of the SDLP party. He played a vital role in bringing American influence to bear on both the British and Irish governments at key moments in the peace process, and had a hand in convincing President Clinton to remain strongly involved.
And while many politicians who espoused Irish causes ran for the hills when Sinn Fein president Gerry Adams came to the U.S., Senator Kennedy was there to greet him. In fact, he was instrumental in persuading President Clinton to grant Adams a visa in February of 1992. 
Bill Clinton and Hillary Clinton 
As major supporters of the Irish peace process, Bill and Hillary Clinton moved mountains. The 42nd President of the United States took the strongest position on Irish issues ever taken by an American president.
In 1994 he granted a visa to Sinn Fein president Gerry Adams, fulfilling a campaign promise and stating "the U.S. cannot miss this rare opportunity for our country to participate in the peace process."
Then in November, 1995, President Clinton became the first sitting American president to visit Northern Ireland. He and Hillary were greeted by tens of thousands of people lining the streets in Derry and Belfast. It was the first of several visits that the Clintons made to Ireland.
The First Lady would also play a leading role in moving the peace process along. She helped create links between the White House and leaders on the ground, and worked closely with women on both sides of the divide at a time in the conflict when women's voices were hardly heard.
President Clinton's Irish roots are traced through his mother, Virginia Cassidy Kelley, who was the granddaughter of Irish immigrants, "poor Irish farmers," as she called them. The Cassidys are believed to have emigrated from Ballycassidy, Co. Fermanagh.
In March, 1996, President Clinton was Irish America's Irish-American of the Year.
In March, 2007, Hillary Clinton was named Irish America's Person of the Year. She lost out on the Democratic Party nomination for the 2008 presidential election, and was appointed Secretary of State in the Obama administration.
Tip O’Neill
Thomas Phillip "Tip" O'Neill Jr. (1912-1994) was an unashamed liberal and a major political force in the Democratic Party for decades – and he was also responsible for one of the most quoted political expressions of all time: “All politics is local.”
He served in the House of Representatives and was the second-longest-serving Speaker of the House.
He was grew up in near Barry’s Corner, in North Cambridge, Massachusetts, referred to at the time as “Little Dublin” because of the Irish presence there.
His entry into politics came when he was 15, when he campaigned for fellow Irish-American Al Smith, who was running in the 1928 presidential campaign against Republican Herbert Hoover. (Smith lost that election, in part due to anti-Catholic bigotry.) In the next presidential election, O’Neil campaigned for Franklin D. Roosevelt.
Perhaps one of O'Neill's crowing achievements as Speaker in the House was his work on Northern Ireland. With fellow Irish-American politicians Hugh Carey, Edward Kennedy, and Daniel Patrick Moynihan, O’Neil worked tirelessly for peace in Northern Ireland.
In 1977, the “Four Horsemen” as they famously became known, issued the “St. Patrick’s Day” declaration, where they denounced violence in the North. O’Neill was a strong advocate of giving aid to Northern Ireland and put pressure on the British government to adopt a more even handed approach in their handling of the conflict.
O'Neill died in 1994. Bill Clinton said at the time: “Tip O'Neill was the nation's most prominent, powerful and loyal champion of working people... He loved politics and government because he saw that politics and government could make a difference in people's lives. And he loved people most of all."
His old rival, Bob Dole, called O’Neill “the Congressman's Congressman.”

Ronald Reagan
Ronald Reagan, U.S president from 1981-1989, can trace his Irish roots to the small town of Ballyporeen in Co. Tipperary.
Church records show that Reagan’s grandfather, Michael Regan was baptized in the town in 1828 and lived there until his left for the U.S in the 1860s. (While there he changed the spelling of his name.)
When Reagan visited Ireland in the 1984, he visited the village and told the residents about his Irish background. 
That visit, however, was controversial. A lot of Irish were very unhappy about U.S foreign policy in Central America, especially its support of the Contras in Nicaragua. 
Irish folk singer Christy Moore sang a song around this time called “Hey Ronnie Reagan” which contained the memorable lines,
“Hey, Ronnie Reagan, I'm black and I'm pagan.
 I'm gay and I'm left and I'm free.
 I'm a non-fundamentalist environmentalist.
 Please don't bother me. “
Dr. Garret FitzGerald, the former Irish prime minister in power when Reagan visited Ireland, said that once Reagan discovered his roots he embraced them.
“He regularly dined in the Irish Embassy and he didn’t dine in any other embassy in Washington. Perhaps some sentiment and some politics,” FitzGerald said.
Barack Obama
President Obama can trace Irish his ancestry on his mother's side back to one Falmouth Kearney from Monegall, County Offaly, whose father was a shoemaker. According to Church of Ireland rector Canon Stephen Neill whose investigation into Obama's Irish roots was prompted by a request from an Americans for Obama group based in Dublin, Falmouth emigrated to New York in the 1850s at the age of 19.
Falmouth's daughter Mary Ann Kearney, born in Tipton County, Indiana in 1869, married Jacob William Dunham, of Kempton, Indiana. The couple moved to Wichita, Kansas, where their great-granddaughter, Barack Obama's mother Ann Dunham, was born in 1942.
Barack Obama himself was born in Hawaii, where his mother's parents had moved and where she attended college and met Obama's father, Barack Hussein Obama from Kenya. The couple divorced when Obama was two.
Obama was educated at Columbia University. In 1991 he graduated from Harvard Law School where he was the first African-American president of the Harvard Law Review. In January of 2005 he was sworn into office as state senator in Illinois.
As presidential hopeful, Obama had the support of the tiny Irish town of Monegall in Co. Offaly where locals celebrated the senator's victory in the Iowa caucus. Standing outside of Ollie Hayes's pub, American Democratic activists led locals in the signature Obama cheer, "Fired Up! Ready to Go!"
And after Obama won the election last November, one Moneygall resident, Ollie Larkin, said: "The last time I saw this excitement was when we won the senior county hurling in 1975. We're only a small, little parish and how proud we are."
Al Smith
Al Smith didn’t win the 1928 presidential election – but he did pave the way for JFK some 32 years later, and made history by becoming the first Irish American and first Catholic to run for president for one of the two major parties.
He grew up in New York’s Lower East Side and although his four parents each had different ethnic backgrounds (Irish, German, Italian and English) it was his Irish background that he most identified with. His mother was Catherine Mulvehill Smith, and her parents had immigrated from Co. Westmeath to New York in 1841. Famous for his gift of the gab, he impressed influential parishioners of St. James Church in Lower Manhattan (where he had served as an altar boy) with his verbal dexterity.
In 1918, he became governor of New York and throughout the following decade, he was one of New York’s Irish most focal spokesmen. Throughout his political career, he championed the rights of America’s immigrants.
In 1928, he secured the Democratic Party nomination for president. But his religion was too much for some Americans, who feared that as a Catholic, his loyalty would lie with Rome and not his own country. The Rev. Bob Jones, of the famous South Carolina Christian fundamentalist university that bears his name, famously said of Smith’s presidential ambitions: “I’d rather see a nigger as President.”
One reporter famously said that Smith lost the presidential race because of the three P's: Prohibition, Prejudice and Prosperity.
Joseph McCarthy
Joe McCarty was an Irish-American politician who was the Senator from Wisconsin from 1947 until his death in 1957.
He was one of the most vigorous anti-communist crusaders during the Cold War, and his name became synonymous with exploiting U.S paranoia of communism.
There were Irish roots on both sides of his family: his mother, Bridget Tierney, was from Co. Tipperary, while his father, Timothy McCarthy, was born in the U.S the son of an Irish father and a German mother.
He served in the Air Force during World War II, and later during his political career, he used his war record to his own advantage, especially when he up against opponents who didn’t serve in the military.
In 1952, McCarthy appointed Robert Kennedy as assistant counsel of the Senate Permanent Subcommittee on Investigations, a Senate committee which was carrying out investigations into alleged communist activity in the US.
Kennedy resigned in 1953 but according to a biographer, he "retained a fondness for McCarthy."  When televised hearings were carried out into McCarthy’s conduct in 1954, Robert could be seen in the background.
McCarthy died in 1957 from alcoholism.