The north wall and east gable have vanished entirely. The south wall, at 19.5 metres long and no more than 1.4 metres high at its tallest, is the most substantial surviving element, interrupted by two gaps that may once have been doorways or window openings. A small fragment of the west gable, five metres long and roughly a metre high, is all that is left of that end of the building. The church occupies the western quadrant of a graveyard, perched above steep escarpments to the north, east, and south, which lends the site an odd, elevated quality despite the modest scale of what survives.

The name Duagh derives from the Irish Dubháth, meaning black ford, and the parish sat within the medieval diocese of Ardfert and the barony of Clanmaurice in north Kerry. By the fifteenth century the church had become entangled in a web of ecclesiastical finances that stretched well beyond the parish itself. The rectories of Duagh and the neighbouring parish of Cúil-Ó-dTaidhg had been appropriated to the Augustinian monastery of St Mary at Connall in County Kildare, which received a combined annual pension of one mark sterling from the two parishes. In practice, it was the Cistercian abbot of O'Dorney, Edmund, who managed, or farmed, those revenues locally on Connall's behalf. By 1466, however, a dispute had arisen: a figure named Maurice Fitzmaurice, described in a papal letter of that year as a clerk of the diocese of Ardfert and as someone who was powerful, had withheld the tithes from both Connall and O'Dorney. The matter was referred to the abbot of Ratoo, another Kerry monastery, with papal instructions to summon all parties and restore the arrangement if the facts were found to be as stated. The dispute was still generating paperwork in 1483, when a Patrick Fitzmaurice is recorded as succeeding an Edmund Fitzmaurice as priest of the parish, a coincidence of surnames that hints at how deeply the Fitzmaurice family had embedded themselves in the ecclesiastical affairs of north Kerry.

The ruins lie within a graveyard that remains in use, built out over the same limestone shelf as the old church walls. The escarpments that drop away on three sides are worth noting on approach, giving a sense of why this particular outcrop was chosen as a building site in the first place.