An iron bar still supports the front lintel of a recessed opening, though the rear of the structure has long since collapsed. What survives is a lime kiln, a type of industrial furnace once common across rural Ireland, where limestone was burned at high temperatures to produce quicklime for use in agriculture and building mortar. The stone-lined funnel at the top, around 1.6 metres in diameter, is now overgrown, but its form is still legible.

Lime kilns of this kind were working features of the agricultural landscape from at least the seventeenth century onward, and their distribution across Cork reflects both the county's geology and the practical demands of farming on acidic soils. Spreading lime on fields reduced that acidity and improved crop yields, which made access to a local kiln genuinely important for smallholders and larger estates alike. This example at Knockahorrea is built directly into a hillside, a characteristic arrangement that allowed fuel and limestone to be loaded into the funnel from above while the burnt lime was raked out through the draw arch below. The lintelled recess with its iron bar support is the remnant of that lower opening. The roadside position was deliberate too, making it easier to bring in raw material and carry away the finished product by cart.