The Declaration of Independence was adopted on July 4, 1776, by the Second Continental Congress in Philadelphia. Drafted primarily by Thomas Jefferson, it announced that the 13 American colonies were breaking away from British rule to form a new, independent nation. The document outlined key principles of liberty, equality, and the right to self-government. Its adoption marked the formal beginning of the United States of America and is celebrated every year as Independence Day. The Declaration remains a powerful symbol of freedom and democracy.