The Mountjoy was a merchant ship used to relieve the Siege of Derry in Ulster in 1689.

The “Mountjoy” that saved starving Scot-Irish of Londonderry, Northern Ireland, in 1689.

Twenty years later, these same people immigrated to Lancaster Pennsylvania.

Pennsylvania

Mountjoy Township was named first in 1759, followed by the village of Mountjoy in 1812. Mount Joy was incorporated into a borough in 1851.

It was also the codename for the ship used in the 1914 Larne Gun Running.