Kentucky joined the union on June 1, 1792, the 15th state. Tennessee joined four years later, on June 1, 1796, becoming the 16th state.
Kentucky’s admission to the union pushed the U.S. flag to 15 stars and 15 stripes. President George Washington signed the law that authorized the U.S. flag be expanded to 15 stripes in early 1794. I’ve not pinned down the history of what happened next. So far as I know there was no law expanding the flag to 16 stripes, and in 1818, Congress said the flag would be 13 stripes, and stars equal to the number of states.
A 15-striped Star-spangled Banner that flew over Fort McHenry in Baltimore Harbor in 1814 and inspired Francis Scott Key to write the poem that is now the lyric to our national anthem. President James Monroe signed the 13-stripe law in 1818.
What happened in between? I suspect there are a lot of 15-stripe flags, but it wouldn’t surprise me to find a 16-stripe flag somewhere. A variety of stars-and-stripes flags cropped up, which the 1818 law was intended to squelch.
Residents of the Bluegrass State and the Volunteer State should fly their flags today, in honor of their state’s having joined the union on June 1.