The key document declaring the American colonies free from British rule is the Declaration of Independence, adopted on July 4, 1776. Drafted primarily by Thomas Jefferson, this document articulated the colonies' grievances against King George III and asserted the inherent rights of individuals, including life, liberty, and the pursuit of happiness. The Declaration served as a bold proclamation of the colonies' desire for autonomy and influenced democratic movements worldwide. Its adoption marked a significant turning point in the American Revolutionary War, signaling the colonies' united commitment to pursue independence and establish a new nation based on Enlightenment ideals.