The document that proclaimed the United States' independence from Britain is the Declaration of Independence, adopted on July 4, 1776. Drafted primarily by Thomas Jefferson, the Declaration articulated the American colonies' grievances against King George III and articulated the philosophical justification for independence. It emphasized the rights to life, liberty, and the pursuit of happiness, grounded in Enlightenment ideals. The document served not only as a formal announcement of separation from British rule but also laid the foundational principles for the formation of a new nation. July 4 is celebrated annually as Independence Day in the United States.