The modern U.S. flag has 13 stripes, representing the original thirteen colonies that declared independence from Great Britain.
The Continental Congress specified the thirteen-stripe design in its Flag Resolution of June 14, 1777. The resolution called for alternating red and white stripes and thirteen white stars on a blue field. The stars represented a new constellation formed by the united states.
The flag briefly had 15 stripes after Vermont and Kentucky joined the Union. The Flag Act of 1818 restored the number of stripes to 13 while establishing the practice of adding a star for each new state. This prevented the flag from becoming increasingly crowded as the country expanded.
The present flag has 50 stars, one for each state, but its 13 stripes continue to recall the founding generation. Hawaii’s admission in 1959 produced the 50-star design, which first became official on July 4, 1960. Thus the flag combines a permanent reference to the original colonies with a changing representation of the Union.