The doorway alone would make this small ruined church worth seeking out. Its round arch is carved with chevrons, a decorative zigzag pattern characteristic of Romanesque stonework, and the jambs on either side carry a pellet design and capitals bearing carved heads: a human face on the north side, a ram on the south. North of the arch, a stone lion's head gazes out from the wall; its counterpart to the south has long since vanished. Two bullaun stones, shallow basin-like depressions worn or carved into boulders and associated with early Christian ritual use, sit outside the entrance. The whole ensemble is compressed into a building barely nine metres long, set within a small rectangular graveyard defined by an earthen bank, close to the floodplain of the River Suir.

The church is known both as the parish church of Guilcagh and, in older sources, as the church of Foilinge. A record from 1615, cited by the historian Power, notes that it was repaired that year, suggesting it was still in some form of use in the early seventeenth century, though it was already old by then. The Romanesque style of the doorway points to construction several centuries earlier, likely in the twelfth century. By the early 1920s the fabric had deteriorated enough to require conservation work, which is what preserved the walls to their present height of between one and three metres. Several significant objects found here have since left the site: an effigy of a bishop inscribed S. MONNIA EPISCOPS, a seventeenth-century graveslab, fragments of a chest tomb, and two quern stones used for grinding grain all passed to the National Museum of Ireland, or were lost entirely before they could be recorded properly. An altar built into the east wall remains in place.