A souterrain is an underground stone-lined passage, typically constructed during the early medieval period, and used variously for storage, refuge, or as a place of concealment. Most of what lies beneath these two stones remains unknown, the passage having been recorded as inaccessible at the time of survey.

The souterrain sits in association with a cashel, a type of stone-walled enclosure that served as a fortified farmstead in early Christian Ireland. Together, the two features suggest a settlement of some antiquity, the underground chamber positioned deliberately within the northern portion of the enclosure. D. Lavelle's archaeological survey of the Ballinrobe district, published in 1994 by the Lough Mask and Lough Carra Tourist Development Association, recorded the site and noted the two visible capstones, but the structure itself could not be entered or properly assessed at that time. How much of the original passage survives underground, and what condition it is in, remains an open question.