The Continental Congress adopted the first United States flag resolution on June 14, 1777.
The resolution specified thirteen alternating red and white stripes and a blue field containing thirteen white stars. It described the stars as representing a new constellation, but it did not prescribe the exact arrangement later associated with the flag.
The thirteen stripes and stars referred to the original states. As new states joined the Union, Congress changed the flag’s design in later years. The Flag Act of 1794 added stars and stripes for Vermont and Kentucky, while the Flag Act of 1818 returned the number of stripes to thirteen and allowed stars to increase with statehood.
June 14 is now observed as Flag Day in the United States. The date is unrelated to the Star-Spangled Banner, a different flag made in 1813 with fifteen stars and fifteen stripes for the expanded Union.