On September 9, 1776, the Second Continental Congress formally renamed our nation the United States of America. This replaced the term United Colonies, which had been in general use.
In a declaration dated September 9, 1776, the delegates wrote:
“That in all continental commissions, and other instruments, where, heretofore, the words ‘United Colonies’ have been used, the stile be altered for the future to the “United States.”
Words are important and severing the colonial moniker was a key step toward ultimate independence.
Michael Carver -- Historical Interpreter/Reenactor 