This souterrain, a type of artificial cave commonly found across Ireland, was discovered with its roof formed by large stone flags; a distinctive architectural feature that would have required considerable effort to construct. The flags have long since been removed, and today there's nothing visible on the surface to indicate that this hidden chamber ever existed beneath the good farmland of the ridge.

Souterrains like the one at White Hill are fascinating remnants of Ireland's past, typically dating from the early medieval period between the 6th and 12th centuries. These underground passages and chambers served multiple purposes; they may have been used for food storage, taking advantage of the cool, stable temperatures below ground, or as temporary refuges during times of conflict. The construction method using large flag stones as roofing suggests this was a well-built example, though without excavation it's impossible to know the full extent or layout of the underground spaces.

The site was recorded as part of the comprehensive Archaeological Survey of County Donegal, compiled in 1983, which catalogued field antiquities from the Mesolithic period through to the 17th century. While the physical evidence at White Hill has vanished from view, the documentation ensures this piece of Donegal's archaeological heritage isn't forgotten entirely, even if modern visitors would walk right over it without knowing what lies beneath their feet.