The remains are so reduced that archaeologists cannot say with confidence whether the original building was a simple undivided church or a more elaborate nave-and-chancel structure, the two-part arrangement common to early Irish ecclesiastical sites where the nave housed the congregation and the chancel was reserved for the clergy. The ruins sit in the north-east quadrant of an oval-shaped graveyard, a shape that itself signals early medieval origins, oval and curvilinear enclosures being characteristic of the earliest Christian foundations in Ireland. Beyond the graveyard, a curving field boundary to the north marks the ghost of a larger ecclesiastical enclosure. Lough Derravaragh lies 160 metres to the south-south-west, a lake better known from the myth of the Children of Lir, and the church overlooks its shoreline.

Tradition attributes the founding of the site to Diarmuid, son of Lughna, a figure said to be possibly descended from the Uí Fiachrach, an early Irish dynastic grouping. The foundation is placed in the sixth century, and Diarmuid later became the patron saint of the parish. The placename Faughalstown derives from Fochlaid, and the site may have functioned as a proprietary church of the Uí Fiachrach Cúile Fobair, meaning a church under the ownership and control of a particular kin group rather than a freely independent foundation. What the walls themselves can still tell us is modest but not nothing. The structure, roughly 19.5 metres long overall, was built from random limestone rubble. A gap about two metres wide in the south wall of the nave, slightly off-centre to the west, may indicate where a doorway once stood, though no dressed stonework remains to confirm it. A rebate, a recessed ledge cut into the wall face, is visible in both the north and south walls and marks where the chancel originally met the nave. A single jamb of a window, broken out long ago, survives in the south wall. The interior is now so overgrown with briars and vegetation that no further detail can be read from ground level.