America250's anniversary commemorates the adoption of which founding document?

America250's anniversary commemorates the adoption of the Declaration of Independence.

The Second Continental Congress adopted the Declaration on July 4, 1776. The document announced that the thirteen American colonies regarded themselves as independent states and explained their reasons for separating from Great Britain.

The anniversary is therefore dated from 1776, rather than from the Constitutional Convention of 1787 or the Constitution's ratification in 1788. Those were crucial later events in the creation of the United States, but neither supplies the date used for America250.

Thomas Jefferson drafted the principal text, while the Continental Congress debated and revised it. The parchment document is now preserved at the National Archives in Washington, D.C., alongside other founding records.