Congress adopted the United States Declaration of Independence in 1776, the year commemorated by America250.
The Second Continental Congress approved the Declaration on July 4, 1776, in Philadelphia. The document announced that the Thirteen Colonies regarded themselves as free and independent states rather than colonies subject to the British Crown.
The Declaration followed the Lee Resolution, which Congress approved on July 2. That resolution stated that the colonies were independent; the Declaration then explained the reasons for the break and presented the decision in a formal public document. This is why July 2 and July 4 both appear in accounts of independence, although July 4 became the national anniversary.
The parchment copy most people recognize was signed primarily on August 2, 1776, rather than in one grand ceremony on July 4. The distinction between adoption, publication, and signing is a common source of confusion. America250 specifically marks the 250th anniversary of the Declaration’s adoption in 1776.