It measures roughly 19 metres east to west and 13 metres north to south, rising only about half a metre above the surrounding ground. That modest profile is partly the result of centuries of ploughing and land reclamation, which local knowledge suggests have steadily worn it down from a once more considerable height.

What the mound represents is a fulacht fia, a type of prehistoric cooking site found in considerable numbers across Ireland. The typical fulacht fia consists of a trough, usually dug into the ground near a water source, and a hearth for heating stones. Stones were placed in the fire until red-hot, then dropped into a water-filled trough to bring it rapidly to the boil. After repeated use, the cracked and spent stones were piled to one side, and it is these discarded heaps of fire-shattered material that form the distinctive horseshoe-shaped or oval mounds visible today. Most date to the Bronze Age, broadly between 2000 and 500 BC, though examples span a wider range. The one at Killabraher follows the familiar pattern: an accumulation of burnt material that has outlasted everything else about the activity it once served.