The event commemorated on July 4th in the United States is the adoption of the Declaration of Independence in 1776. This pivotal document proclaimed the thirteen American colonies' separation from British rule, articulating foundational principles such as equality, natural rights, and the right to self-govern. Drafted mainly by Thomas Jefferson, the Declaration notably emphasized the idea that governments derive their powers from the consent of the governed. July 4th has since become a national holiday, symbolizing American democracy and independence, celebrated with fireworks, parades, and various public festivities across the nation.