The United States Declaration of Independence was unanimously adopted on July 4, 1776.
The Second Continental Congress approved the document in Philadelphia, formally announcing that the thirteen American colonies considered themselves independent states rather than colonies of Great Britain. Thomas Jefferson wrote the main draft, while Benjamin Franklin, John Adams, Roger Sherman, and Robert Livingston helped revise it as the Committee of Five.
July 4 marks adoption, not the date every delegate signed the famous engrossed parchment. Most delegates signed that copy on August 2, 1776, and several others signed later. The Declaration had also been debated before its final wording was approved.
The date became the foundation of the United States national Independence Day celebration. The document itself explains the political case for separation and lists grievances against King George III, making it both a revolutionary announcement and a statement of political principles.