A souterrain is an underground or semi-subterranean stone-lined tunnel, typically associated with early medieval settlements in Ireland, used variously for storage, refuge, or as an escape route in times of danger. This one, just over six and a half metres long and more than two metres wide, sits at the southern entrance to a ringfort, the circular earthen enclosure that once formed the boundary of a defended farmstead. The combination of souterrain and ringfort in a single site is not unusual in early medieval Ireland, but the setting here gives the place a particular character. The surrounding terrain is hummocky and broken, the kind of landscape that rewards those who know where to look.

The drumlin ridge on which the site sits rises above a deep valley to the north-west, and the views from it take in both the Dartry Mountains and the Ox Mountains, two distinct upland ranges that frame much of the Sligo and Leitrim landscape. A drumlin is a smooth, elongated hill formed by glacial action, and in counties like Sligo they tend to cluster in rolling, irregular patterns that made them attractive to early settlers for their natural defensibility and drainage. Whoever chose this particular summit had an eye for ground. The ringfort and its souterrain would have been well-positioned to monitor movement across the surrounding valley, while the sunken passage offered concealment below the surface when visibility from above became a liability rather than an advantage.