Measuring only about 4.3 metres by 3.6 metres internally, with walls a mere 0.6 metres thick, it is far too modest to be a conventional church. Tradition holds that Mass was said here in secret during the Penal Laws, that period from the late seventeenth century onward when Catholic worship was suppressed under a series of legislative restrictions, and priests risked transportation or execution for practising their faith. A narrow doorway opened in the east wall; a crude altar was set against the west. Beyond the doorway, the foundations of a larger enclosure suggest the building may once have sat within a more deliberately arranged space, though what that enclosure served is now unclear.

The building was described in some detail by Redington in 1912, who recorded its dimensions, the altar, and the doorway, and also noted two stone troughs lying to the north-west, one roughly three metres from the structure and another about twelve metres beyond it. Their purpose was not explained, and when surveyors later returned to locate them, they could not be found. What does survive today are heavily overgrown sections of the west, north, and south walls, none of them rising above 0.6 metres, along with the altar itself. The west wall is the most substantial remnant, running to about four metres in length. The rest is low, fragmentary, and largely reclaimed by vegetation.