The front of the structure has collapsed, but what remains is enough to read the process: a stone-lined funnel, roughly two metres high and just over a metre across, where limestone and fuel were loaded and fired together, and a broad earthen ramp, twelve metres long and nearly five metres wide, rising from the south-east to allow carts or workers to tip material in from above. The interior stone is burnt and vitrified, fused by the sustained heat necessary to convert limestone into quicklime.

Lime kilns were a fixture of Irish farming life from the eighteenth century well into the twentieth. Quicklime, produced by heating limestone to high temperatures, was spread across acidic soils to improve fertility, and mixed into mortars and whitewashes for building work. The design of this kiln, with its loading ramp and funnel-shaped draw kiln, was the standard workhorse model of the era. Dating to the early twentieth century, the Tooreenfineen example is a relatively late survival of a technology that was already being displaced by commercially produced agricultural lime by the time many such kilns fell out of use. The vitrification of the stonework, where the lining has essentially been glazed by repeated intense firing, gives a sense of just how often and how hard the structure was put to work during its active life.