What was partially uncovered here is a fulacht fia, a type of ancient burnt mound found widely across Ireland and typically understood as a site where stones were heated in fire and then dropped into a water-filled trough to bring it to the boil, most likely for cooking. The one at Quignashee sits in a hollow beside a watercourse, in drumlin country where the rounded glacial hills leave wet, low-lying ground between them, precisely the kind of soggy, stream-rich landscape where these sites are most commonly found.

The excavation took place in November 2005, carried out by S. Zajac under licence ahead of road-widening works by Mayo County Council along the N59. By that point the site had already been heavily compromised: the road had clipped its eastern edge, and modern land drains had cut into its western and south-western sides. What survived was patchy but legible. The burnt mound, roughly 12 metres north to south and up to 5.2 metres wide at its north-eastern end, consisted of heat-fractured stones packed into a dark, charcoal-rich soil. Beneath that layer, to the north of centre, excavators uncovered a small unlined trough pit cut directly into the subsoil, measuring roughly 1.2 metres by 1 metre and between 0.4 and 0.6 metres deep. Around it was a broader disturbed area of subsoil, interpreted as a possible later attempt to widen the trough. A small posthole sat just 0.4 metres to the east of the trough, and fragments of decayed wood were found mixed into the surrounding burnt stones. A piece of oak beside the trough appeared to be a tree root rather than worked timber. A separate pit was also visible higher in the sequence, cut into the burnt mound layer itself, suggesting the site saw more than one phase of activity. A rath, an enclosed circular farmstead of early medieval date, lies about 300 metres to the west, hinting at a broader pattern of long-term human activity in this stretch of the Mayo countryside.