Taoiseach Simon Harris has congratulated Donald Trump on his inauguration as the 47th President of the United States.
In a statement, Mr Harris said he wished Mr Trump "every success in his term-in-office".
"This is a very important moment for President Trump personally and for the United States. As the torch of democracy passes peacefully from one leader to the next, I send him, and the people of the United States, my very best wishes."
Mr Harris said the Government looks forward to cooperating with President Trump and his administration in the months and years ahead.
"In doing so, we will be building on the strong, enduring, and dynamic relationship between our two countries, a relationship that draws strength from our deep, historical people-to-people connections, the support of the US with peace on this island, as well as our growing and mutually beneficial economic relationship."
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Meanwhile, Tánaiste Micheál Martin has offered his "warmest congratulations" to President Trump.
In a statement, Mr Martin said: "Ireland's close ties with the United States are built on generations of shared history and a rich tapestry of connections between our peoples.
"On this historic day, the American people can be assured that Ireland will always remain a constant and reliable partner and friend."
Mr Martin said the relationship between Ireland and the US has matured into a rich, dynamic and mutually beneficial political and economic partnership.
"Our two-way economic relationship exceeds €1 trillion every year. Our task is to further strengthen this partnership, and to create sustainable jobs and prosperity on both sides of the Atlantic," he said.
I also think today of the long road to peace and reconciliation on this island, and of how much we owe to successive US administrations for their constant support for a brighter future for all on this island.
