For America250, 13 stripes on the U.S. flag represent the original colonies that became the United States.
The flag has seven red stripes and six white stripes, arranged horizontally. Their number has remained 13 even as the country expanded from the original colonies to 50 states. The stripes therefore preserve a reference to the founding era rather than showing the current number of states.
The blue canton contains stars representing the states. Congress approved the first official national flag in 1777, specifying 13 stars and 13 stripes. When Vermont and Kentucky joined the Union, the flag temporarily gained additional stars and stripes, but Congress restored the stripe count to 13 in 1818 while continuing to add stars for new states.
The modern flag has 50 stars, reflecting the admission of Hawaii in 1959. The current 50-star design became official on July 4, 1960. A common mix-up is to assume that both stars and stripes count states; only the stars do so on the present flag.