A souterrain is an underground passage or chamber, typically built during the early medieval period in Ireland using stone-lined walls and a corbelled or lintelled roof, and most often associated with nearby settlement or burial sites. Here, the surface offers almost nothing to the eye, just two gentle hollows in the earth, yet they point to something constructed deliberately beneath.

The depressions lie approximately twenty metres south of a burial ground, a proximity that is not unusual in the Irish landscape, where souterrains frequently appear close to ecclesiastical enclosures or early cemeteries. Whether they served as places of refuge, storage for perishables, or had some other function is a question that applies across the type generally. At Killaveenoge, no excavation appears to have been undertaken to confirm the structure's form or date, and what is known rests on local information rather than any formal investigation. That the site has been noted at all is largely because the pattern of two collapsed entry points or roof-fall depressions at a consistent spacing is a recognised signature of these underground features when seen from the surface.