The United States Declaration of Independence was approved by the Second Continental Congress on July 4, 1776.
Congress had already adopted the Lee Resolution on July 2, declaring the colonies independent. The Declaration then explained the reasons for that decision, including grievances against King George III and principles of natural rights.
The document was debated and edited over several days. Its approval date became the foundation of the United States Independence Day celebration, although the parchment engrossed copy was signed mainly on August 2.
A common mix-up is treating July 2 as the Declaration's approval date. July 2 marked the independence vote; July 4 marked approval of the Declaration's final text.