This is a fulacht fia, a type of prehistoric cooking site found in large numbers across Ireland, typically Bronze Age in date. The usual interpretation is that stones were heated in a fire and then dropped into a water-filled trough to bring it to boiling point, the shattered and blackened remnants accumulating over time into the characteristic horseshoe or kidney-shaped mound that survives today.

The mound at Canagullen is roughly kidney-shaped and substantial, measuring around ten metres on its longest axis and rising to just over three metres in height, which places it at the larger end of the scale for this monument type. What makes it particularly worth attention is the way a narrow stream, less than two metres wide, has cut through the western tip of the mound, isolating a smaller D-shaped portion from the main body. Both sections show exposed burnt material at the point of separation, and more scorched stone is visible along a sheep path that skirts the northeastern arc of the main mound. The proximity of the site to a tributary of the Glanmore River is entirely typical; access to running water was a practical necessity for whoever used this place, and fulachta fiadh cluster along watercourses throughout the Irish landscape. An enclosure of some kind lies roughly forty metres to the west, suggesting this corner of the hillside saw sustained use across at least some portion of prehistory.