During groundworks for a dwelling house at Ballynakill, near Edenderry in County Offaly, a spread of burnt mound material turned up in the soil, sitting quietly along the line of the proposed access route. Burnt mounds are among the most common prehistoric monuments in Ireland, typically consisting of cracked and fire-shattered stone mixed with charcoal and ash, thought to be the debris from repeated cycles of heating water, possibly for cooking, bathing, or industrial processes. They are modest things to look at, but they accumulate over long use, and their presence in the ground tends to signal sustained prehistoric activity at a particular spot.

The discovery was made on 21st August 2022, when archaeologist Caoimhe Ní Thóibín carried out test trenching under licence number 22E0543 as a condition of the planning permission. Four linear trenches were opened across the development footprint, including the driveway corridor and percolation area. The burnt mound spread appeared at the southern end of the first trench, measuring 4.24 metres north-south and between 1.05 and 1.95 metres east-west. A small hand-excavated section through the middle of the visible material revealed it to be only around 0.03 metres deep, which suggested either that what was exposed was the outer edge of a larger mound extending beyond the trench, or simply a shallow, dispersed spread. The material was cleaned, recorded, covered with geotextile, and the trench backfilled. Rather than disturbing the archaeology further, the recommendation was to raise the driveway above the existing ground level using layers of sand and graded stone, preserving the burnt mound material in place beneath it.