Minister for Foreign Affairs Simon Coveney will hold talks in Washington DC with the Speaker of the US House of Representatives, Nancy Pelosi.
On the agenda will be US-Irish relations, Northern Ireland, Brexit and the Covid-19 pandemic.
While on Capitol Hill, Mr Coveney will also meet Senators and Representatives from both political parties, including members of the Friends of Ireland Caucus.
Mr Coveney was in New York yesterday for the United Nations General Assembly and met UN officials and government representatives, including Russian Foreign Minister Sergey Lavrov.
"We'll be talking through where the debates on the Protocol are likely to go … to a very informed group of people who have taken a close interest in this"@simoncoveney will hold talks in Washington DC with @SpeakerPelosi later today | More: https://t.co/d1uWoUkOOo pic.twitter.com/g2Pey6KwkC— RTÉ News (@rtenews) September 23, 2021
He spoke to reporters before leaving New York and was asked if he had been in contact with Katherine Zappone after her controversial appointment as a special envoy.
"No I haven't. I've been busy this week and I'm sure Katherine Zappone makes her own decisions. I haven't spoken to her this week," Mr Coveney said.
He was also asked if he believes Ms Zappone should have agreed to appear before the Oireachtas Committee on Foreign Affairs.
"Once somebody leaves public life, they are a private citizen and they make their own decisions. That's the position on Katherine Zappone," he said.
Looking ahead to his meetings in Washington today, Mr Coveney said he expects to be met with a reception that will be informed, accurate and firm in terms of the importance of the Northern Ireland Protocol to protect the peace process and ensure there is no return to a hard border.
Meanwhile, Minister for Finance Paschal Donohoe has spoken with US Treasury Secretary Janet Yellen about the current OECD process that aims to reform global corporation tax rules.
Taoiseach Micheál Martin has chaired a meeting of the UN Security Council on the issue of climate and security.
Also today, President Michael D Higgins delivered a virtual address to the United Nations Food Systems Summit.
It follows on from meetings the President had in Rome last week, where he said the world is not on track to achieve the 2030 Agenda for Sustainable Development and that modern food systems.
Today, he said: "Whether or not we transform these systems is the test of our authenticity, in the words we use while so many are dying of hunger.
"The need for action is now more urgent than ever – we meet in the shadow of a global pandemic; in a world struggling with new, rising, deepening inequality; a world scarred by unprecedented levels of conflict and instability; and facing climate and biodiversity emergencies which threaten our very future on this planet.
"Ending world hunger and ensuring the right to food for all must be placed firmly at the top of the political agenda," said President Higgins.