The name alone carries the weight of what it represents. During the Penal Laws of the seventeenth and eighteenth centuries, Catholic worship was banned or severely restricted across Ireland, and priests who celebrated Mass risked transportation or death. Communities gathered instead in remote or inconspicuous spots outdoors, using a flat rock as an improvised altar. The landscape of Connacht, with its broken limestone terrain and scattered field systems, lent itself to exactly this kind of concealment.

The rock here is a natural outcrop of limestone aligned roughly north-northeast to south-southwest. Its upper face measures about 2.9 metres in length, tapering from 1.6 metres wide at one end to just 0.5 metres at the other, giving it something of a wedge-shaped profile. The eastern side sits relatively low, around half a metre above the ground, while the western face rises to 1.8 metres, with a steep drop into a narrow gully running along that side. What makes this site particularly interesting is the evidence of continued or commemorative use. Abutting the eastern face is a small landing, roughly 2.3 metres by 1.3 metres, constructed partly from natural rock outcrop and partly from poured concrete. Two flights of steps lead up to it, one formed from the natural rock, the other added in concrete at some later point. A house now stands about 2.5 metres to the southwest, and a stream runs to the east, so the rock sits in a lived-in, working landscape rather than any kind of preserved isolation. The community evidently saw fit to make the site more accessible rather than simply leave it to the field.