This is what remains of a wedge tomb, a type of megalithic burial monument built during the late Neolithic and early Bronze Age, characterised by a gallery that narrows and lowers towards one end. The Maryfort example has collapsed to the point where only one sidestone and the capstone are clearly visible above ground, yet the structure retains a quiet presence that earlier map-makers clearly felt warranted marking. The 1921 edition of the Ordnance Survey six-inch map names it simply "Cromlech", an older, loosely applied term for megalithic structures that was once common in popular and cartographic usage.

When Ruaidhrí de Valera and Seán Ó Nualláin catalogued this monument in their 1961 Survey of the Megalithic Tombs of Ireland, they recorded a circular mound of roughly 4.5 metres in diameter surrounding the tomb, though they were candid that much of it had likely accumulated from field clearance rather than representing original prehistoric fabric. The tomb itself, had it survived intact, would have been orientated along a northeast-southwest axis, the typical alignment for wedge tombs in Ireland. The northeast sidestone is now gone, or more precisely, it may have fallen and been swallowed by the soil; there is a slight swelling in the ground beneath that end of the capstone which suggests the stone could still be lying prostrate beneath the sod and vegetation. The surviving northwest sidestone is of weathered limestone, smoother than the capstone, though cracked at one corner. The capstone measures 1.8 metres by 1.7 metres and bears the kind of irregular pitting produced by long exposure to rainwater dissolving the limestone surface, a process known as solution weathering.

The tomb sits within the former Maryfort Estate, on improved pasture and parkland ground. The small timber enclosure built around it offers a degree of protection, though the proximity of industrial development to the southeast means the setting is far removed from any sense of rural isolation. What strikes a visitor is the disproportion between the modest scale of what remains, just a few stones on a gentle rise, and the considerable age of the thing, a burial place constructed thousands of years before the estate, the factory, or the fence existed.