The cashel, a type of stone-walled ringfort typically associated with early medieval settlement and farming, was already an ancient structure when someone decided its solid masonry made a convenient backing for an industrial furnace. The kiln itself is a post-1700 construction, built at a time when lime burning was a common agricultural practice across rural Ireland, used to produce quicklime for spreading on acidic soils or for use in mortar and whitewash. That a farmer or labourer chose to lean the new structure against the old one rather than build it freestanding suggests a pragmatic eye for what was already standing and sturdy.

The pairing of monuments at Gortnahoula is a small but telling example of how the Irish landscape accumulated use over time, with later generations treating earlier structures as raw material or ready-made infrastructure rather than as curiosities to preserve. The site did not appear in the Sites and Monuments Record of 1989 but was brought into the Record of Monuments and Places by 1995, suggesting it was recognised as worth protecting, if belatedly. The lime kiln itself would have functioned by loading alternating layers of limestone and fuel, typically turf or wood, into a stone-lined bowl or draw kiln, then burning them down to produce calcium oxide. The heat required was considerable, and the process would have left the surrounding area thick with dust and fumes for the duration of the burning.