The 1777 Flag Resolution established the first congressional description of the U.S. flag on June 14, 1777.
The resolution was adopted by the Second Continental Congress during the American Revolutionary War. It specified thirteen alternating red and white stripes and thirteen white stars on a blue field, representing the thirteen United States. It did not prescribe the stars’ exact arrangement.
The resolution created the design foundation for later U.S. flags, but it did not establish the modern fifty-star flag. Stars were added as new states joined the Union, while the number of stripes was fixed at thirteen in 1818.
The date is also commemorated annually as Flag Day. The popular story that Betsy Ross designed the flag is not established by the 1777 resolution itself; historians generally describe the early flag as the work of multiple makers and designers.