In what year did Kentucky become the 15th state to join the union?

The story behind the answer

Kentucky became the 15th state on June 1, 1792. It had been the western frontier of Virginia, and after several conventions and petitions—made easier under the new U.S. Constitution—Congress admitted Kentucky as the first state west of the Appalachians. The other dates don’t fit: 1782 was during the Revolutionary War, 1788 marks the Constitution’s ratification (not Kentucky’s statehood), and 1798 is too late.

Context tip: think of early statehood moving