That single slab, thickest at its leading edge and sloping sharply downward toward a ground-fast rear stone, gives the monument a distinctive wedge-like profile that is hard to ignore once you are standing beside it. Land clearance in recent years has opened up the immediate surroundings considerably, which means the structure now sits with less visual shelter than it once had, exposed and unambiguous in a working pastoral landscape.

A portal tomb is among the earliest forms of megalithic architecture in Ireland, typically consisting of two tall upright portal-stones at the entrance, a blocking stone between them, and a large capstone balanced across the whole. Here at Kiltiernan, the two portal-stones angle forward toward the west, framing the entrance to a long rectangular chamber that runs roughly four and a half metres in length and opens to the west. When archaeologist Marcus Ó hEochaidhe excavated the chamber, he recovered a chert arrowhead, three hollow scrapers, and an end scraper. These are tools closely associated with the Early Neolithic period, placing the tomb's use in a time several thousand years before the earliest written records in Ireland. The monument received a preservation order as far back as 1936 under the National Monuments Acts and has since been taken into State Guardianship, listed as National Monument 343.

The tomb sits within Kiltiernan Domain, south County Dublin, accessible from the general Kiltiernan area near the foothills of the Dublin Mountains. The surrounding pasture is rock-strewn and uneven underfoot, so sturdy footwear is sensible. The chamber opening faces west, which means the interior catches the afternoon and evening light particularly well. The scale of the capstone is best appreciated from the eastern side, where the sharp downward slope toward the ground-fast rear stone becomes fully visible and the sheer engineering ambition of the Neolithic builders becomes quietly apparent.