It is a mound barrow, a type of prehistoric funerary monument in which earth, and sometimes stone, was piled above a burial to create a lasting mark on the landscape. This one is modest in scale but precise in its proportions: roughly ten metres across at the base east to west, nine metres north to south, tapering to a flattened top just two metres wide, and rising to a height of between one and a half and one point six metres. That careful geometry, still legible beneath the turf after what may be thousands of years, is what makes it worth pausing over.

Barrows of this kind are broadly associated with the Bronze Age, though some belong to earlier or later periods, and without excavation it is difficult to say more about who built this one or when. What can be said is that the choice of location was deliberate. Drumlin ridges, the long whale-backed hills formed from glacial deposits, were frequently used as sites for burial monuments across Ireland. Placing a barrow at the summit would have made it visible across the surrounding lowlands, a feature that was almost certainly part of the point. The ridge at Knockarush gives the mound a natural prominence that no amount of additional height could have improved on.