The oval spread, roughly thirteen metres long and seven metres wide, is filled with cracked stones and blackened earth, the accumulated debris of a practice that was once commonplace across the Irish landscape but whose full purpose is still debated by archaeologists.

Burnt mounds are among the most frequently recorded prehistoric monument types in Ireland, yet they remain relatively little understood in terms of their precise function. The prevailing theory holds that they were used for cooking, essentially large outdoor boiling pits in which stones were heated in a fire and then dropped into water-filled troughs to bring the liquid to temperature. Some researchers have argued they also served as saunas or bathing facilities. Either way, repeated cycles of heating and rapid cooling cause stone to fracture, and that fractured, fire-blackened rubble is what gradually mounds up into the distinctive deposits archaeologists now recognise. The proximity of the Ballylane example to a small stream running roughly northwest to southeast, about thirty metres to the east of the mound itself, fits the pattern well. Access to a reliable water source appears to have been a consistent feature of these sites wherever they occur.

The site is not visible as an upstanding monument. Its existence becomes apparent only under cultivation, making it the kind of place that surfaces briefly, season by season, before disappearing again under new growth.