On what date did Congress officially adopt the name “United States of America”?

Congress officially adopted the name “United States of America” on September 9, 1776. The phrase had already appeared in the Declaration of Independence, but Congress later made it the country’s formal name.

Before that decision, revolutionary documents often referred to the colonies as the “United Colonies.” The change reflected the political transformation created by independence: the colonies claimed to be separate, sovereign states joined in a common cause.

The Declaration’s original title used the wording “The unanimous Declaration of the thirteen United States of America.” Congress had approved the Declaration on July 4, but the formal naming resolution came more than two months later.

This date is distinct from Independence Day. July 4 commemorates adoption of the Declaration, while September 9 marks Congress’s decision about the nation’s official name. Both belong to the founding chronology remembered during America250.