The circular earthwork enclosure that once occupied elevated ground near the confluence of the Gaddagh and Laune rivers had been levelled by the early twentieth century, leaving nothing visible above the surface. Yet underneath it, largely intact, was a souterrain, an underground passage and chamber system of the kind typically associated with early medieval ringforts in Ireland, hand-dug through the earth and used variously for storage, refuge, or concealment.

The souterrain was documented by Cooke in 1906, by which point the ringfort above it had already been destroyed. Access into the underground system was gained through the collapsed roof of the northernmost chamber, a detail that captures something of the site's condition even then. That first chamber, oval in plan and aligned northwest to southeast, measured roughly seven feet long by just under five feet wide, with its floor sitting some seven feet below ground level. A narrow creepway, barely eighteen inches high, connected it southward to a larger, subrectangular chamber measuring twelve feet in length and over five feet wide. A second creepway, again less than two feet high and roughly nineteen inches wide, led further south to a third chamber aligned east to west. This final chamber was at least six feet long, though its eastern end was blocked by collapse at the time of recording. The sequence of tight, low connecting passages between wider chambers is characteristic of souterrain construction; the creepways would have made movement through the system slow and difficult, which was presumably the point.