John O'Donovan noted it around 1840, and it remains there still, smothered and invisible. That small fact captures something of the quality of the place: features present but concealed, a building that has retreated into itself while continuing to hold its ground within a near-circular graveyard, roughly 58 metres across, bounded by an earthen bank and hedge. The church sits on a gentle spur of land, with a stream that loops around to the south and west, giving the site a quietly enclosed feeling.

The parish takes its name from Caomhán Santleathan of Ardcavan, a saint whose feast fell on the 12th of June, and that date continued to matter locally well into the nineteenth century, when patterns, traditional gatherings held at a sacred site combining prayer with communal festivities, were still being observed at St Cavan's Well about 600 metres to the southwest. In 1615, a visitation by Thomas Ram, the Protestant bishop of Ferns, recorded that Henry Reigh was rector, and that both the church and chancel were in good repair. The structure that survives, considerably less intact, consists of a nave and a smaller chancel. The nave's north wall has been entirely removed, and the chancel walls are heavily reduced or rebuilt into a nineteenth-century mortuary enclosure. What does remain is legible: a pointed doorway of undressed stone in the south nave wall, two buttresses flanking it, and a rounded chancel arch, just over two metres wide, leading through to the chancel, where a tomb niche can still be made out in the north wall. A slit window beneath the ivy-hidden bellcote is visible if you look for it.