Mr Biden took the opportunity to speak about Northern Ireland at the St Patrick's Day gala dinner.
"Sixteen years after signing the Good Friday Agreement, issues like flags, parades and how to treat the past still divide communities," he said.
"All-party talks were established to help work through these painful and difficult issues, those talks were chaired by Richard Haass, a man respected by everyone in Northern Ireland, the United Kingdom, the Republic of Ireland and the United States.
"That by the way, is no mean feat. Richard Haass set out proposals on how to move forward, the all-party talks have not reached agreement yet, but out of those talks came some good substantive proposals that can provide the basis of progress going forward."
He added: "So we encourage Northern Ireland's political parties to keep going."
Mr Biden quoted Belfast Methodist student and dinner guest Hannah Nelson, who introduced President Barack Obama at Belfast's Waterfront Hall during his visit last year.
"She said: 'As a 16-year-old, I don't want to live in the past, I want to live in the future, for peace to be an actual reality. We all need to take responsibility for the present.'
"Hannah is right, for peace to be an actual reality people like Hannah shouldn't have to worry about what colour uniform they wear, whether they can walk through certain neighbourhoods, whether it matters if they support rugby or hurling."
UTV Political Correspondent Tracey Magee, who is in Washington, attended the event.
He was very much urging our politicians to get on with the business of sorting out the three outstanding issues of flags, parades and the past.
UTV's Tracey Magee
"He was at times quite pointed, implicitly criticising them for how they had treated Dr Richard Haass, the talks chairman, who is of course an American, and saying that 16 years is too long for these matters to be outstanding," Tracey Magee explained.
Taoiseach Enda Kenny, who is in Washington to take part in St Patrick's Day celebrations, gave the keynote address.
Northern Ireland's leaders are also in the US for the main festivities.
On Friday morning, First Minister Peter Robinson and deputy First Minister Martin McGuinness addressed the annual NI Bureau breakfast.
The ministers, who have been on a trade mission in the country, reacted to Mr Biden's comments ahead of a face-to-face meeting with him.
"The issues are yet unresolved and issues that we have to face up to. We have to find a solution to them and we are continuing to work until we do, so we're always happy to have encouragement when we come here to overcome the obstacles that are there," Mr Robinson told UTV.
Mr McGuinness added: "The fact that he turned the bulk of the speech over to what was happening in the north of Ireland was very significant indeed and I think within it we can see a certain level of dissatisfaction that we haven't finally concluded the work of Richard Haass and Megan O'Sullivan.
"As Peter has said rightly, and I have said also, these are issues that aren't going away. The past, parades and the whole issue of identity needs to be tackled - it is our duty and responsibility."