That detail alone sets this site apart. The cashel, a type of early medieval stone ringfort enclosed by a dry-stone wall, contained within its interior a souterrain, an underground tunnel or chamber system typically used in early medieval Ireland for storage, refuge, or both. By the time the antiquarian Thomas Johnson Westropp recorded it in 1905, the structure was already in mixed condition, its fate shaped as much by wildlife as by the passage of centuries.

Westropp described a linear passage running some 63 feet, roughly 19 metres, in total length. The northern end had been opened up and damaged, the consequence of efforts to drive out badgers that had taken up residence in what he called the 'dark and covered way'. That collapsed mid-section, around 21 feet in length, had become a grassy trench visible at the surface, while the southern portion remained largely intact for a further 27 feet, ending at a cross-wall positioned about 24 feet from the cashel's south wall. Off this intact southern section, Westropp noted several small lateral chambers branching away from the main passage, a detail that suggests a more complex underground layout than a simple corridor. When the site was inspected again in July 1998, no surface trace of the souterrain could be detected at all, the grassy trench and any remaining visible features apparently lost to time and vegetation.