The structure is a souterrain, an underground passage or chamber, typically drystone-built, associated with early medieval ringforts across Ireland and thought to have served as storage space, refuge, or both. What makes this one worth pausing over is its relative completeness: two chambers of meaningful size, connected by a low creep, the narrow crawl-through opening that linked separate sections of these underground systems and would have made any unwanted entry considerably awkward.

The souterrain sits within the southern half of a ringfort, a type of enclosed farmstead common in early medieval Ireland, usually defined by an earthen bank or stone wall. The first chamber runs east to west, measuring around twelve metres in length and roughly 1.7 metres wide, though its eastern half has been robbed out, meaning stone was removed at some point, likely for reuse in field walls or buildings nearby. Access today is through a displaced roof lintel, one of the large flat stones that would originally have formed a tight, concealed ceiling. A short connecting passage, about four metres long and less than a metre wide, leads from near the south-west end of the first chamber into a second, which runs north-west to south-east and extends to around eight metres. The structure was documented by Costello in publications from 1902 and 1903, placing it among the earlier formally recorded underground monuments in Connacht.