Martin McGuinness and Peter Robinson with President George W Bush at the White House
The first and deputy ministers met President George W Bush in Washington on Tuesday.
President Bush congratulated Peter Robinson and Martin McGuinness on the role they played in re-establishing the political institutions at Stormont.
Mr Robinson wished the president well in the future.
While Mr McGuinness said the meeting confirmed that "despite many competing demands they enjoy access at the highest level in the USA".
They have now travelled to New York where they will meet with Mayor Michael Bloomberg, New York City Comptroller General William Thompson, New York State Comptroller Thomas Di Napoli and Chief Executive of the New York Stock Exchange, Duncan Niederauer.
The first minister said they hoped to secure the economic future of Northern Ireland.
"Over the coming days we will meet with some of the most powerful men in the United States. Never before have we had access to such vast pools of potential investment," Mr Robinson said.
Mr McGuinness said the trip showed Northern Ireland was "very attractive to potential investors".
"The fact that some of the world's biggest funds and indeed the world's biggest stock exchange are keen to meet with us, even in this gloomy economic climate, sends out a very clear signal," he said.
On Monday, the first and deputy first ministers spoke to some of the largest and most profitable companies in the US at a Fortune 500 dinner.