Known in Irish as Carraig an Aifrinn, Mass Rocks have their origins in Penal times (1695 to 1756) when the Catholic faith was proscribed in Ireland. Whilst the Penal Laws managed to limit the public expression of Catholicism, they did not ensure the elimination of the Catholic faith or result in the mass conversion of Catholics (Bartlett 1990, 2). Despite Mass Houses being closed and chapels appropriated by Protestant authorities, Mass continued to be celebrated secretively in barns, out-houses, and hidden private chapels. It was frequently celebrated under trees and bushes, in ditches and in the open air at altars known as Mass Rocks situated in fields, glens, and on mountain sides. Mass Rocks played a crucial role in maintaining Catholic identity and ensuring the survival of the Catholic faith. 
In order to remain hidden, Mass Rocks are often located in remote or inaccessible places. Many are situated on private land, overgrown and difficult to access so this data set provides a series of images taken during the researcher’s field research in Ireland