The building is modest in scale, roughly 13.7 metres by 5.5 metres, and by the time the Ordnance Survey recorded it in the nineteenth century the gables had already fallen, leaving only about 8 metres of north wall standing. Two defaced windows and a round-arched doorway were all that remained of its architectural detail. Around it, aerial photographs taken in 2005 revealed earthworks to the east, south, and west that may represent medieval fields or the traces of an earlier settlement, suggesting the church was once part of something considerably larger.

The antiquarian Thomas Johnson Westropp, writing in 1904 and 1905, gathered the documentary thread that ties the ruin to its founders. He identified the church, known in Irish as Teampall Dhún Dónaill, as the chapel of a castle belonging to a Norman family who appear in the records under various spellings: Donndonenolde, Dundonenyld, Dundonoyl. The earliest reference to a Robert of this line dates to 1201, and by 1237 the benefices of his lands near Rathgel had been resigned to Keynsham Abbey. By 1291 a chapel was recorded as attached to the castle. The church was formally dedicated to St. Mary Magdalen on 22nd July 1410, and appears in subsequent records as Downdonill in 1418. A rental document of 1452 refers to it as Harold's Castle, rendered in Irish as Cloghanarold, which is how the townland is known today. The nearby holy well dedicated to St. Molua is also recorded in association with the site.

The ruin lies on the demesne lands associated with Cloghanarold House and Castle, the latter standing approximately 210 metres to the north-north-east and close to the southern bank of the River Deel. Access to the site requires attention to its position within private demesne land, so enquiries locally would be advisable before visiting. The earthworks visible in aerial imagery are far less legible on the ground, but the surviving north wall and the doorway give enough to anchor the imagination. The association with St. Molua's Well nearby offers a further point of interest for those tracing the layered religious geography of this corner of Limerick.