The rectangular church, oriented roughly northeast to southwest and measuring about sixteen metres long by six metres wide, has lost every architectural detail to time and weather. No carved stonework, no window dressing, no dressed jambs remain. The probable entrance, positioned towards the southern end of the northwest wall, can only be inferred rather than seen. What distinguishes the site is not the building itself but what wraps around it: a D-shaped enclosure, roughly thirty-five metres east to west and twenty-five metres north to south, defined by a drystone wall, the kind of construction built without mortar, relying entirely on the careful placement of stone against stone.

Enclosures of this shape, curving on one side and flattening on the other, are a recurring feature around early ecclesiastical sites in Ireland, and their presence often suggests origins considerably older than any surviving masonry. The enclosure wall at Carrownacroagh is best preserved at the west and northeast, but much of it has been obscured by field clearance over the generations, as farmers gathered loose stone from the surrounding land and added it to boundaries, blurring the original line. The church itself sits within this enclosure in a state of near-total collapse, its walls reduced to low rubble spread across the footprint of what was once a small but purposeful structure. No documentary record attached to the site appears to have survived either, leaving the building without a dedication, a founder, or a date that can be pinned down with any confidence.