It is easy to mistake for a natural feature, a slight rise in a field, until the shape resolves itself: the characteristic curved form of a fulacht fia, one of Ireland's most common yet least explained prehistoric monument types.

A fulacht fia, in its simplest description, is a cooking or heating site. The typical arrangement involves a trough dug into the ground, usually lined with wood or stone, filled with water, and heated by dropping fire-cracked stones into it. Those stones, once shattered by repeated heating and cooling, were discarded to form the distinctive horseshoe mound around the trough. Thousands of these sites survive across Ireland, most dating to the Bronze Age, and the burnt, fragmented stone they contain makes them immediately recognisable even after millennia of weathering. The Tooreenmore example was recorded in 1985 as part of the Castleisland District Archaeological Survey. At that time the mound measured 16 metres from north-west to south-east and 11.6 metres across its other axis. The back of the mound was 8.3 metres wide, and the opening, facing roughly south-east, spanned 5 metres. On its eastern side the mound stood 1.3 metres tall, making it one of the better-preserved points of the structure. The interior, where the trough would once have been, was already showing the effects of cattle using the depression as a resting spot, its surface pocked and churned by hooves.

The site sits close to the main road towards Castleisland, which runs to its south-east. The wet pasture setting is entirely typical; fulachtaí fia are almost invariably found near water sources, and the rush-covered ground around this one suggests the moisture that would originally have made the location practical for its purpose.