Brood X cicadas will emerge in 15 states: Delaware, Illinois, Georgia, Indiana, New York, Kentucky, Maryland, North Carolina, New Jersey, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, Michigan, as well as in Washington D.C.
The next appearance has been predicted to occur in 2038, according to Wikipedia.
Some Brood X emergents were four years early, appearing throughout the brood's range in 2000 and in the Baltimore, Maryland-Washington, D.C., area in May 2017.