The discovery was made during groundworks for the Ballyhaunis Water Supply Augmentation Scheme, and only the portion of the site that fell within the pipeline's path was excavated. The western section of the mound remains buried where it was left in the Middle Bronze Age.

A fulacht fia is a type of ancient cooking or heating site found in great numbers across Ireland, typically consisting of a mound of fire-cracked stones discarded after repeated use, alongside a water-filled trough. At Devlis, the mound was low and irregular in shape, measuring roughly six metres by seven and a half metres, and composed of heat-shattered sandstone fragments packed in charcoal-rich soil. A subrectangular trough, just over two metres long and cut directly into the earth, sat at the south-western edge of the mound. The method generally involved heating stones in a fire and dropping them into the water-filled trough to bring it to boiling point, a process that gradually destroyed the stones and built up the surrounding mound over time. Before excavation, the site had already been disturbed by centuries of cultivation and drainage work, so what survived was a partial picture. Radiocarbon dating of two charcoal samples placed the site's use firmly in the Middle Bronze Age, with calibrated dates falling between approximately 1736 and 1657 BC. A single piece of struck chert, a flint-like stone shaped deliberately by hand, was also recovered from the site, hinting at activity in the wider landscape across a long span of time.