Irishman Gen Stephen Moylan , an aide-de-camp to general George Washington during the American Revolution is credited with being the first person to write “United States of America”. He used the term United States of America in a letter to a fellow officer in the continental army. This is not to say he was the first to use the term orally.
According to Michelle O’Mahony, a history consultant, Moylan used the term in a letter dated January 2nd/3rd, 1776, well before it was used in the declaration of independence on July 4th, 1776.
“Moylan used the term in a letter to Col Joseph Reed, who was also one of George Washington’s aides-de-camp, in which he expresses his desire to travel to Spain and serve as a representative of what he explicitly calls the United States of America,” said Ms O’Mahony.

FROM THE LIBRARY OF CONGRESS
LINK: Introduction - Irish American Resources at the Library of Congress - Research Guides at Library of Congress

Since the founding of the Jamestown colony in Virginia in 1607, Irish people have immigrated to and settled in America. From politics to a nation-wide appreciation of St. Patrick’s Day, every aspect of American history and culture reveals the extensive influence of Irish Americans and the significance of their ethnic identity.
This guide introduces the wonderful primary and secondary resources on Irish American heritage available through the Library of Congress. A variety of formats can be explored including audio recordings of interviews and music, photographs, and historic newspaper articles. In addition to the freely available online resources from the Library of Congress’s collections, selected online resources from sites outside of the Library of Congress are also listed. Additional materials such as printed books and subscription databases are available onsite at the Library of Congress and through other libraries.

Notable American actors with Irish ancestry