The rear has gone entirely, and the arched recess at the base, where workers would once have raked out the finished product, measures just over a metre high and a little more than two metres wide. It is a modest ruin, easy to overlook, but the proportions recorded at the site tell you something precise about how it once worked.

Lime kilns were a fixture of the Irish agricultural landscape from at least the seventeenth century onward, used to burn limestone at high temperatures and produce quicklime, which farmers spread on acidic fields to improve soil fertility. The design at Ballyhonock follows a well-established pattern. A stone-lined funnel, beaker-shaped in cross section and reaching a maximum diameter of around 2.2 metres, would have been loaded from the top with alternating layers of limestone and fuel, usually coal or wood. The hollow and the slope behind the structure are not incidental; building into a hillside made it easier to load material from above while the arched draw hole at the front allowed the finished lime to be extracted from below. The site essentially used its own topography as part of the machinery.