The United States Flag Act established the first official national flag design in 1777.
The Second Continental Congress passed the Flag Resolution on June 14, 1777. It specified thirteen alternating red and white stripes and thirteen white stars on a blue field, representing a new constellation. The resolution did not specify the stars' exact arrangement, so early flags appeared with different patterns.
The original thirteen stripes symbolized the Thirteen Colonies. Later flag changes added stars for new states while preserving the thirteen stripes. In 1795, Congress authorized fifteen stars and fifteen stripes after Vermont and Kentucky joined the Union; the stripe count returned to thirteen in 1818.
The design is often linked to Betsy Ross, but historians have not established that she created the first American flag. The Betsy Ross story became popular decades later, while New Jersey delegate Francis Hopkinson is associated with several early flag designs. June 14 is now celebrated as Flag Day.