This is a wedge tomb, a type of megalithic burial monument built during the late Neolithic and early Bronze Age, typically orientated with its higher, wider end facing west. The one at Ballyganner does exactly that: nearly two metres tall at the western end, it slopes down to roughly one and a third metres at the east, its trapezoidal shape preserved within a grass-covered oval mound measuring about twelve metres across. The local name on the Ordnance Survey maps of 1842 and 1920 was simply 'Cromlech', an older, catch-all term once used for prehistoric stone structures before more precise classifications emerged.

The antiquarian T. J. Westropp visited in 1901 and was puzzled by two channels on the upper face of the capstone, concluding they were water-worn, formed long before the block was ever raised into position. The limestone slabs themselves carry other marks of time: a vertical crack through the western centre of the north sidestone, a natural cavity breaking the top edge of the south sidestone near its western end, and a western endstone whose upper north corner was already broken, in relatively recent times according to the archaeologists Ruaidhrí de Valera and Seán Ó Nualláin, who surveyed the tomb in detail for their 1961 volume on Clare's megalithic monuments. They found the eastern endstone reduced to its base, its upper portion obscured by a drystone wall, though they noted it may once have closed the chamber entirely. Inside, the floor is lower and uneven, with at least three flat slabs laid near the western end. A further inspection carried out in 1997 found nothing had changed.

The tomb sits on a gentle south-west facing slope in rough pasture, set within a much larger, multi-period field system that suggests the landscape around it has been shaped and reshaped across many centuries. The upright stone set on its long edge in the north-western part of the mound, aligned north-west to south-east, is an additional detail easy to overlook from a distance, but worth noting once you are standing near the mound itself.