It is featureless along most of its length, save for the ghost of a window at the western end, a detail that corresponds closely with a window surviving in the nave of a nearby church within the same graveyard. That the entire complex was once marked simply as 'Abbey' on Ordnance Survey six-inch maps gives some sense of how completely it has receded from the landscape.

The site has a long layered history. A monastery was founded here by St Colmcille, and the early church bore the Irish name Teampull Choluim Cille in his honour. At some point, probably before 1170, the Augustinian rule was introduced, most likely that of Arrouaise, a reformed congregation from northern France that was particularly active in Ireland during the twelfth century, and the community became the Priory of St Mary. It was dissolved by 1540, in the broad sweep of monastic suppression under Henry VIII. The site then passed through secular hands: leased to Christopher Nugent, Lord of Delvin, in 1567, and to Thomas Philipps in 1570. By 1605, a grant described it as the 'late monastery or priory of canons of the Holy-Island', and it was awarded to Mary, Lady Delvin, widow of Christopher Nugent, and her son Sir Richard Nugent. A bronze bell, reputedly recovered from the site, survived the dissolution and the intervening centuries and is now kept in St Columbkille's Roman Catholic Church in Aghnacliff village, a building dating to 1834. The island also holds a holy stone roughly 150 metres to the south-south-east of the priory remains, and a fortification some 330 metres to the south-east, suggesting the island carried more significance, across more periods, than its present quietness implies.