The front wall has collapsed, leaving the interior open to view: a barrel-shaped, stone-lined funnel roughly 2.3 metres in diameter and about four metres high, the kind of structure that would once have been fired continuously to burn limestone down into quicklime. A lime kiln is essentially an industrial furnace, typically fed with layers of limestone and fuel from the top and drawn as burnt lime from a lower arch at the front. That front arch is now mostly gone, though a few voussoirs, the wedge-shaped stones that form an arch, remain to indicate where the recess once was.

Lime kilns of this type were common features of the Irish rural and coastal landscape from the early modern period onward, producing quicklime used in agriculture to reduce soil acidity and in building as a base for mortar and whitewash. Positioning a kiln against a cliff face was a practical choice: the rock provided structural support and insulation, and a coastal location allowed limestone and fuel to be landed by boat without the difficulty of overland transport. The Millcove kiln fits this pattern precisely, its back pressed into the cliff while its working face opened towards the shore. The collapse of that face, though it speaks to centuries of exposure, has incidentally turned the kiln into something more legible than most, the full depth and shape of the funnel now visible in a way it would never have been during operation.