The first official U.S. flag adopted by Congress had 13 stars.
On June 14, 1777, the Continental Congress passed the Flag Resolution describing a flag with 13 alternating red and white stripes and 13 white stars on a blue field. The stars represented the 13 United States, meaning the former colonies that had declared independence from Great Britain.
The resolution did not specify how the stars should be arranged, how many points each star should have, or whether the stripes should begin with red or white. As a result, early flags appeared in several designs. The circular arrangement popularly associated with the Betsy Ross flag is one later interpretation, not a layout required by the 1777 resolution.
The modern flag has 50 stars, one for each state, but it retains 13 stripes for the original colonies. New stars have been added as states joined the Union, while the number of stripes was fixed at 13 by the Flag Act of 1818.