The building is tiny, measuring just 5.2 by 4.2 metres internally, and was constructed without mortar, its flat slabs laid in careful horizontal courses. Near the top of the north wall, there is a faint tendency towards corbelling, the technique of projecting successive stone layers inward to eventually close a roof, though the walls do not survive high enough to show how far this was carried. The west end-wall preserves a trabeate doorway, meaning one formed with flat lintels rather than an arch, here doubled, standing less than a metre high at present ground level. Set into the east wall is a small splayed niche with a stepped base, probably intended for a lamp or a small devotional object.

The site sits on gently sloping land between Slievagh mountain and the Ferta river, and the modern graveyard that now encloses it has almost certainly erased earlier features. By the early 1840s, a stone structure described as an altar was recorded a short distance east of the oratory, where it served as the focal point for stations, the rounds of prayer and ritual movement once commonly performed at sacred sites across Ireland. This feature may have been a leacht, a low commemorative or devotional cairn associated with early Christian practice, but no trace of it now remains. The modern graveyard appears to have absorbed and overwritten whatever broader pattern of early remains once surrounded the oratory. One further object connects the site to its medieval past: a handled wooden vessel, dated to the medieval period, was recovered from the graveyard during the 1940s and is now held by the National Museum of Ireland.