An emotional US Vice-President Joe Biden praised the "can do" attitude of Irish people as he departed after a six-day tour of the country.
Mr Biden described how his youngest grandchild Hunter didn’t want to go home after a trip that took in Dublin, Mayo and Louth.
He said that the connection between Ireland and the United States was stronger than ever.
“I think there is virtually nothing we cannot do,” he said when reflecting on the common traits between the two countries.
His swansong before leaving office next January was tinted with sadness as he explained how the trip “back home” was all his son Beau’s idea.
Beau (46) died last year of brain cancer.
Speaking at a lunch in Farmleigh before flying back to Washington on board Air Force Two, Mr Biden said: “My son Beau talked about it, when I got elected, he said: ‘Dad, we’ve got to go to Ireland as a family and we’ve got to go back to your roots’.
“Beau passed but he’s with us all the days. This is the culmination of a discussion we’ve been having in the family for a long, long time,” he said.
He made the unusual step of thanking the Irish press for both following him and for giving him space.
His abiding memory will be walking down Garden Street in Ballina and reflecting on what his great-great-great grandfather Edward Blewitt must have being thinking when he left during the Famine.
“It must have been like an American wake to leave everything behind. To board a ship to go to a country that you didn’t know much about and at the time there wasn’t a big ‘welcome’ sign, saying come.
“It took an enormous amount of courage and it must have been incredibly sad,” he said.
“I consider myself incredibly fortunate to not only have gotten an opportunity to know An Taoiseach and Fionnuala and your children.
“It’s a phrase used lightly in international politics ‘I’ve become your friend’. But I really consider Enda a friend. He has been incredibly generous to us,” Mr Biden said.
The Taoiseach described the vice-president as “a friend of Ireland”.