They are found in their hundreds across the island, yet each one tends to carry its own quietly unresolved quality, existing mostly as a hollow in the landscape, unmarked and uninterpreted, known mainly to those who farm or walk the land directly above it.

Askillaun sits in a part of Mayo that was inhabited long before any written record, and souterrains of this kind are generally associated with the early Christian period, roughly the sixth to the twelfth centuries, often constructed in association with a nearby ringfort or settlement enclosure. The builders corbelled or lined the walls with stone, sometimes roofing the passage with large flat lintels, creating a structure that could survive underground for over a thousand years with relatively little disturbance. The specific history of this particular example, including when it was first recorded, its dimensions, or its condition, remains undocumented in any publicly available form at present.

Because so little has been formally published about this site, any visitor would be approaching it with very limited guidance. Askillaun is a coastal townland, and the wider area rewards careful attention to the ordinary-seeming ground underfoot, where the past has a habit of lying unusually close to the surface.