When did the stars and stripes become the national symbol?

The Stars and Stripes became the national symbol of the United States with the adoption of the Flag Act on June 14, 1777. This act established the design of the flag, which included thirteen stripes representing the original colonies and a field of stars. Over time, the flag evolved to include additional stars as new states joined the Union, but June 14 is still celebrated as Flag Day in recognition of its significance.