The structure is a cist, a type of grave built from upright stone slabs arranged to form a lined chamber, typically used in the Bronze Age to contain human remains. This particular example is modest in scale, measuring at least 0.6 metres in each direction, with slabs standing to exposed heights of between 0.32 and 0.45 metres on its southern, western, and northern sides. The eastern end remains obscured by the loose cairn stones that have tumbled in around it, so the full extent of the chamber cannot be confirmed from the surface.

The cist does not stand alone but is embedded within a larger burial cairn, a mound of heaped stones raised over the dead. This relationship between cist and cairn is characteristic of prehistoric funerary practice across Ireland and Britain, where the central grave was often the focal point around which the mound was constructed. The cairn at Iskancullin has not been excavated, so whatever human remains or grave goods the cist may once have held remain unknown. What survives is the stone framework itself, partially filled with cairn material, a quiet remnant of a burial tradition that predates written record by several thousand years.