That absence is itself telling. Many prehistoric monuments in Ireland were recorded by the OS during the nineteenth century, but this one on Knocknastaigue slipped through, unacknowledged by cartographers, quietly occupying the highest point of its hill.

The mound was formally described in 1942 and 1943 by O'Kelly, whose account remains the primary record of the structure. At its widest, the monument stretches 38 metres east to west and 15 metres north to south, rising to a greatest height of approximately 2.4 metres at its western end. From there it descends in a series of steps eastward, an unusual stepped profile that distinguishes it from a simple earthen mound. Burial mounds of this general type, raised piles of earth or stone constructed over prehistoric interments, are found across Ireland in various forms, but the stepped descent here is a particular detail worth noting. O'Kelly also recorded irregularly shaped hollows at both ends of the mound, and suggested these may be the result of earlier attempts to dig the monument away entirely. Whether those were casual interventions or more determined efforts at clearance is not recorded. There is no fosse, the term for a surrounding ditch, which is sometimes present around such monuments as part of their original construction.

For those who want to locate the mound, it is worth knowing that it does not appear on standard OS mapping, so modern digital aerial photography is a more reliable guide. The outline of the monument is clearly visible in Digital Globe aerial images, where its oval form and the stepped eastern profile can be traced from above. On the ground, approaching the summit of Knocknastaigue and looking for the subtle rise on the highest point of the hill is the most practical method. The hollows at either end of the mound, remnants of those earlier disturbances, are useful landmarks once you are close enough to read the terrain.