Location
In the nineteenth century there was some confusion about the actual site of the Purgatory — whether it was on Station Island or Saints Island on Lough Derg, County Donegal. For instance the early nineteenth-century Ordnance Survey maps of Ireland (1837–42) locate the Purgatory on Saints Island. However, its location on Station Island is a tradition that continues unbroken from the Middle Ages. It is clearly indicated on documents dating from that time, and it appears as "Caverna Purgatory" on the detailed map of Station Island in Fr. Thomas Carve's book, Lyra Hibernica (1666).
Read more about this topic: St Patrick's Purgatory