The building measures roughly 18.5 metres east to west and just over 7.5 metres north to south, and six corbels, stone brackets once used to support a roof structure or an external feature such as a walkway or lean-to, project from the outside of the south wall. Doorway and window openings survive in both the north and south walls, though any carved or decorative detail has disappeared entirely.

This is what remains of the Benedictine priory of St. Mary on English Island, founded around 1218. The Benedictines, a monastic order following the Rule of St. Benedict, established a number of houses across medieval Ireland, and this small priory on an island off the West Cork coast would have been among the more remote of their foundations. By 1541 it was already recorded as being in ruins, suggesting that the community had abandoned or lost the site well before the general suppression of Irish monasteries under Henry VIII, rather than as a direct consequence of it. The priory sits at the northern end of a graveyard, which itself speaks to the long continuity of sacred use on the site even after the religious house ceased to function.

The church shell sits within the graveyard at the island's north end. The surviving walls are described as being in poor condition despite their relative height, so the fabric is fragile. The corbels on the south wall are the most structurally legible detail remaining, and worth examining closely for what they suggest about how the building was originally arranged.