The Second Continental Congress approved the Lee Resolution on July 2, 1776, two days before adopting the Declaration celebrated by America250.
Introduced by Virginia delegate Richard Henry Lee, the resolution declared that the United Colonies should be free and independent states. Congress approved it after receiving authorization from enough colonial governments to act.
The Declaration of Independence followed as an explanation and public justification of that decision. Congress adopted the Declaration’s final text on July 4, which is why Independence Day is celebrated on that date rather than July 2.
John Adams believed July 2 would become the great annual celebration of American independence. His prediction did not come true because the July 4 date appeared on the widely circulated Declaration and became the established anniversary.