That kind of accidental discovery is, in its own quiet way, a reasonable summary of how much Irish archaeology gets found at all.

The feature revealed is a souterrain, a type of underground stone-lined passage or chamber constructed during the early medieval period, typically associated with nearby settlement enclosures. They were used variously for storage, refuge, or ventilation of surface structures, and their entrances were deliberately concealed. This particular example sits within a small haggard, the enclosed yard attached to a farmstead where hay and other farm goods were traditionally stored, the haggard itself bounded by an earthen bank with a stone face. About twenty metres to the northwest lies a separate enclosure, likely the remains of the ringfort or farmstead the souterrain once served. The proximity of the two features is typical; souterrains almost always appear in close relation to the settlement they belonged to, and finding one generally points to the other.