On what date did the Continental Congress adopt the first U.S. national flag law?

The Continental Congress adopted the first U.S. national flag law on June 14, 1777.

The resolution specified thirteen alternating red and white stripes and a blue union containing thirteen white stars. It stated that the stars represented a new constellation, but it did not specify the stars’ arrangement, the flag’s proportions, or the exact shades of its colors.

The law created a national design during the Revolutionary War, when the United States needed symbols distinct from British flags. Earlier flags used by American forces included the Grand Union flag, which combined British symbols with thirteen stripes. The 1777 resolution removed the British Union from the canton and replaced it with stars.

Later laws changed the flag as new states entered the Union. Congress added stars and, for a time, additional stripes; the Flag Act of 1818 restored the permanent thirteen-stripe arrangement. June 14 is now observed in the United States as Flag Day.