Carved into the natural gradient of Knockroe hill, on the lower south-western flanks below Mount Leinster, a roughly oval platform measuring about eleven metres by nearly eight metres was levelled and reinforced with carefully placed granite stonework. It was built for a purpose that has since become almost invisible from the landscape: the slow, controlled burning of wood into charcoal.

Charcoal-making platforms of this type were designed to support mound kilns, in which stacked cordwood was covered with earth or turf and allowed to smoulder over several days, starved of oxygen to produce the dense, carbon-rich fuel used in metalworking, glassmaking, and other industries that required sustained high heat. The site on Knockroe is one of a cluster of such platforms identified on the same hillslope by Michael Monahan and Edward Butler, suggesting that charcoal production here was not incidental but organised, perhaps even industrial in scale. The platform itself shows careful construction: the uphill north-eastern edge is cut into the slope to a height of around 1.1 metres and lined with stone revetment, while the south-western edge is defined by a scarp reinforced with small granite boulders, resting in turn on a slightly wider revetted step below. The south-eastern edge is similarly scarped. Only the north-western edge has suffered, truncated at some point by a forestry drain. The surrounding hillside is now planted with coniferous forestry, which lends the whole area a somewhat enclosed, anonymous quality, though views open westward over the Aughnabrisky River valley when the terrain allows.