The walls, which rise to no more than 0.6 metres at their highest and run to roughly 10.7 metres along their longer axis, are in poor repair, but their deliberate arrangement is unmistakable. A gap set slightly west of centre in the north wall may mark where a congregation once entered. Local tradition identifies these remains as a Penal chapel, known as the church of Knocknakilla.

Penal chapels belong to one of the more quietly dramatic chapters of Irish religious life. Under the Penal Laws, which restricted Catholic worship in Ireland from the late seventeenth century onwards, Mass was frequently celebrated outdoors or in rudimentary shelters, often on remote hillsides or in places that offered concealment and a swift means of escape. The church of Knocknakilla fits this pattern precisely: its location in open mountain ground, its unassuming construction in random rubble dry-stone, and its modest scale all suggest a building raised not for permanence or display but for practical, clandestine use. A ruined annexe, measuring roughly 5.6 metres by 3.4 metres, is attached to the west-south-west wall, though its original function is no longer clear. That the building survived at all, even in this fragmentary state, is largely due to the durability of dry-stone construction, where walls are built without mortar and rely on the careful placement of irregular stones for their integrity.