The Flag of the United States of America is one of the oldest national standards in the world ---  older than Great Britain’s Union Jack or France’s Tricolor.

During America’s War for Independence, the need for a single national emblem was realized. On June 14, 1777, Congress passed an act stating “that the flag of the thirteen United States be thirteen stripes, alternate red and white, that the union be thirteen stars, white in a blue field, representing a new constellation.” June 14 is now celebrated each year as Flag Day. This design, associated with Betsy Ross, was used until 1795.

In 1794, after Vermont and Kentucky became states, Congress established a flag with 15 stars and 15 stripes. This design, which remained for 23 years, was “The Star-Spangled Banner” Francis Scott Key wrote about in 1814.

Finally in 1818, Congress settled on our current design. They returned to 13 stripes, with the number of stars equal to the number of states --- 
20 at that time.