The document that formally declared the independence of the United States is the Declaration of Independence, adopted on July 4, 1776. Drafted primarily by Thomas Jefferson, it articulated the colonies' grievances against British rule while asserting their right to self-governance. The Declaration emphasized key Enlightenment principles, including individual liberty, the social contract, and the idea that governments derive their power from the consent of the governed. This pivotal document not only marked the birth of the United States but also inspired various democratic movements worldwide, symbolizing the quest for freedom and equality.