The United States Congress passed the Flag Act specifying 13 stripes and 13 stars in 1777.
The law, approved on June 14, 1777, established the first official national flag design. It called for 13 alternating red and white stripes and 13 white stars on a blue field. The stars and stripes represented the 13 states united during the American Revolution.
The statute did not prescribe the exact arrangement of the stars. Later designs commonly placed them in rows, while the circular arrangement associated with the Betsy Ross flag became famous through later tradition and imagery. The law also did not specify many details used in modern flag standards, such as precise proportions.
As new states joined the Union, Congress eventually changed the number of stars and stripes. The Flag Act of 1794 added two stars and two stripes for Vermont and Kentucky. In 1818, Congress restored the stripe count to 13 while continuing to add a star for each new state.