The Franciscan friary in Buttevant, on the west bank of the Awbeg River in north Cork, breaks that pattern entirely. It sat at the centre of the medieval borough, and the most plausible explanation is that it was there first, founded around 1251 by David de Barry, Lord of Buttevant, before the planned town grew up around it. The friars were absorbed into the fabric of the settlement rather than installed at its margins, which makes Buttevant an unusual case in the archaeology of Anglo-Norman urban planning in Ireland.

David de Barry's son, David de Barry II, who died in 1278, was buried in the chancel, and the family continued to use the friary as a principal burial place throughout the medieval period. The building itself was never static. Scholars have identified three broad phases of construction: an initial nave and chancel built after the 1251 foundation, with lancet windows inserted along the south wall possibly in the 1260s and the church subsequently shortened; a south transept, projecting east chapel, and tower added in the 1270s or early 1280s, making them among the earliest known examples of those features in any Irish mendicant friary; and a third phase of extensive reworking in the 15th or early 16th century, including new window tracery, the encasing of the transept in an additional skin of rubble masonry, and a new cloister arcade. By the 16th century the conventual buildings had fallen into ruin, though they were repaired in 1604 and briefly re-inhabited. By 1750 the complex was largely ruinous again. The belfry tower, which had been notable for its banded angle-shafts, described by one architectural historian as unique in Irish towers and possibly a marker of its 13th-century date, collapsed sometime between 1814 and 1819. Only a stub of it survives today, projecting about two metres from the south wall.

What remains is a long single-aisled church, roughly 46 metres end to end, its interior densely occupied by burials from the 18th, 19th, and 20th centuries. The walls carry the evidence of repeated intervention: blocked doorways, tomb recesses with cinquefoil moulded arches, a section of rebuilt wall incorporating fragments of medieval grave slabs and cloister arcading, and a tomb slab with a Latin inscription dated 1625. A section of the south transept, which an 18th-century source called St Mary's Chapel, retains windows with banded shaft surrounds and foliated capitals; part of the blocking in the south gable incorporates a plaque bearing the FitzGerald of Desmond coat of arms. Under the east end of the chancel, a two-level crypt has been interpreted by one researcher as a possible earlier castle or hall, predating the friary itself. The 1851 repairs, carried out after the tower's collapse, consolidated the walls but also embedded loose architectural fragments into the new work, so the fabric of the ruin is, in places, something of a collage of its own history.