Pope Francis announced on Monday he would visit the United States next year, his first trip there as leader of the 1.2 billion-member Roman Catholic Church.
The official confirmation of the trip was keenly awaited in the United States after months of speculation.
Francis told an inter-religious conference on marriage he would go to Philadelphia in September for the Roman Catholic Church's World Meeting of Families, an international gathering.
The trip is also expected to include stops at the White House and Congress in Washington DC and the United Nations in New York, but the pope did not mention those places in his address.
Catholic officials in Philadelphia have said a papal mass in the city would draw up to a million people.
The pope is due to visit Turkey and European institutions in Strasbourg, France in two separate trips later this month.
In January, he travels to the Philippines and Sri Lanka, making his second trip to Asia.