A statement issued by the White House said that the president appreciated "the personal contributions and steadfast support" of Taoiseach Brian Cowen and British Prime Minister Gordon Brown in support of the historic agreement achieved by Northern Ireland leaders.
The deal, said the statement, was "an important step on the pathway to greater peace and prosperity for all communities on the island."
The president, it added, "looks forward to commemorating his second St. Patrick's Day in the White House with the Taoiseach, a celebration which serves as a reminder of the shared history and close kinship between our two countries."
It stated that President Obama would also meet with First Minister Peter Robinson and Deputy First Minister Martin McGuinness in Washington on St. Patrick's Day.
Secretary of State Hillary Clinton, who was being widely credited with critical behind-the-scenes work that helped lead to the eventual devolution deal, said the agreement would help consolidate the hard-won gains of the past decade.
Clinton, who visited Belfast last October, said she has been in regular contact with the Northern Ireland parties and recognized that the path to agreement had been "bumpy."
"This is not the end of the journey. So far, the devolution process has enabled Northern Ireland's leaders to enact a range of needed reforms, from health to housing to environmental safety. Now they have even greater authority, and with that authority comes greater responsibility. They must continue to lead," she said.
"The people of Northern Ireland are poised to build a thriving society on this stronger foundation, a country where neighbors can live free from fear and all people have the opportunity to fulfill their God-given potential."
Clinton said the success of the peace process was an example to conflict-blighted regions across the world.
"Northern Ireland gives us hope that, despite entrenched opposition and innumerable setbacks, diligent diplomacy and committed leadership can overcome generations of suspicion and hostility.
She said the Obama administration, through its Northern Ireland economic envoy, Declan Kelly, would continue its work to ensure future economic development.
She also said that she would host a meeting in Washington with First Minister Robinson and Deputy First Minister McGuinness in the near future to discuss future investment in the North.
"I am confident that people of Northern Ireland will make the most of this moment. And I want to reaffirm the commitment of the United States, and my personal commitment as well, to support Northern Ireland in every way we can," Clinton said.
Congressman Richard Neal, chairman of the congressional Friends of Ireland, also welcomed the deal worked out at Hillsborough Castle.
"The agreement reached at Hillsborough between the political parties is a victory for the people of Northern Ireland and the inclusive power-sharing institutions that represent them.
"It is another significant and transformative milestone that would have been unthinkable a decade ago. The devolution of power will now be complete and the responsibilities of governing on a cross community basis will now be exclusively in the hands of locally elected officials. The new dispensation of partnership and equality promised in the Good Friday Agreement, and the St. Andrews Agreement, is one step closer to reality. With this historic agreement, we are now witnessing the beginning of a new era," said Neal.
"I wish to congratulate First Minister Peter Robinson and deputy First Minister Martin McGuinness for their extraordinary leadership. In my opinion, they have kept their word and delivered for the whole community big time. I look forward to their visit to Washington in March where we can discuss ways to strengthen our relationship, and make Northern Ireland a more peaceful and prosperous society. The United States is deeply invested in the peace process, and our interest and support for the people who live on the island will not waver.
"Finally, I also wish to recognize the work of Taoiseach Brian Cowen and British Prime Minister Gordon Brown. They have taken great risks for peace, and without their efforts, today's breakthrough would not have been possible. They have been steadfast and resolute throughout these negotiations, and the Friends of Ireland in the United States Congress are genuinely grateful for their commitment to making this process work," the Massachusetts Democrat concluded.
Neal's sentiments were reflected by comments from fellow representatives on the House Ad Committee on Irish Affairs, Reps. Joe Crowley (D-NY), Peter King (R-NY) and Eliot Engel (D-NY).
The agreement, said the three, laid out a pathway forward for local control of policing and justice powers with all parties agreeing to undertake a series of steps aimed at complete devolution by April 12.
"While more remains to be done, this announcement is an important and historic step forward towards ensuring long-lasting peace in Northern Ireland.
"We applaud the leaders who worked so hard to secure this critical accord, including Martin McGuinness and Peter Robinson. We also commend Taoiseach Brian Cowen and Prime Minister Gordon Brown for their tireless and courageous efforts in making the Hillsborough Castle Agreement a reality. We would also like to thank U.S. Secretary of State Hillary Rodham Clinton for her steadfast leadership and involvement in the devolution process.
"The dream of peace and complete self-governance for the people of Northern Ireland is one step closer to reality today," the three congressmen concluded.
Senator Chris Dodd described the deal as one that will preserve the power-sharing government and cement the peace process set in motion by the Good Friday peace accord in 1998.
"Northern Ireland, Ireland and Britain's leaders have worked tirelessly and courageously to advance the peace process in the face of political stalemate. I stand committed to working with President Obama and our partners in London, Dublin, and Belfast to ensure that (the) agreement is implemented and sustained," said Dodd, a member of the Senate Foreign Relations Committee who, along with his close friend and Senate ally, the late Senator Edward Kennedy, played a pivotal role in the early involvement of the U.S. in the quest for a lasting peace in the North.
Outside of politics, the deal was given prompt backing by the Ancient Order of Hibernians.
New York State AOH President, Chip McLean, welcomed the agreement and also saw in it a step forward towards a future united Ireland.
"After much work and arduous negotiations, some of which extended into around-the-clock sessions, an agreement has been reached," McLean said.
"Some will find shortcomings with the agreement; however, compromise at times is the key to negotiations. Just as some will take exception to items in the agreement, some also find fault with both Sinn F