The United States flag has thirteen stripes, representing the original thirteen colonies.
The stripes alternate red and white. The Continental Congress specified this arrangement in the Flag Resolution of 1777, which also called for thirteen white stars on a blue field. The stars represented a “new constellation” formed by the independent states.
The flag later gained more stars as new states joined the Union, reaching 50 after Hawaii’s admission in 1959 and the adoption of the current design in 1960. The number of stripes, however, returned to thirteen so the flag would continue honoring the original colonies.
A frequent mix-up is to say that the stripes represent the current states. The stars represent the 50 states today; the stripes preserve the number of colonies that declared independence and formed the original union.