The United States Declaration of Independence was adopted in 1776. The Second Continental Congress approved the document on July 4, 1776, in Philadelphia, formally announcing that the Thirteen Colonies were separating from Great Britain.
The declaration followed the Lee Resolution, which Congress approved on July 2. That resolution stated that the colonies were free and independent states; the Declaration then explained the reasons for the break and presented a philosophical case for self-government.
Thomas Jefferson drafted the document, working with the Committee of Five. The final parchment copy was signed primarily on August 2, 1776, although July 4 marks its adoption and is the date celebrated as Independence Day.
A common mix-up is treating July 4 as the date every delegate signed the document. The date identifies congressional adoption, while the well-known engrossed copy acquired signatures over a later period.