The historic event celebrated on the Fourth of July in the United States is the adoption of the Declaration of Independence in 1776. On this day, the thirteen American colonies declared their independence from British rule, marking the birth of the United States as a nation. The Declaration, primarily authored by Thomas Jefferson, outlines the colonies' grievances against King George III and their desire for self-governance and individual liberties. The Fourth of July is commemorated with various celebrations, including fireworks, parades, barbecues, and public readings of the Declaration, reflecting the values of freedom and democracy.