Penal Laws were imposed by the ruling British on Irish Roman Catholics during the 1600′s and 1700′s, in a bid to force people to accept the reformed Christian faith. There was a ban on the celebration of Catholic Mass, so priests and worshippers had to find hidden areas in the countryside to celebrate Mass. This Mass Rock (Carraig an Aifrinn in Irish) was used as a place of worship and would have been concealed from view to protect the priest and congregation.
This cache can be approached along the famine walk from the ‘Single File’ cache or you can drive up and park outside. If you are doing it as part of the walk, wear boots as it is boggy in places. Even though this is a marked walking trail, it is not well maintained and the trek between here and 'single file' is not suitable for small children.
The GPS may be erratic because of the trees, but you should find yourself on the footbridge.