This underground structure, carved directly from rock, once served as a place of refuge or storage during uncertain times, though today it remains sealed and inaccessible to visitors. The entrance, measuring 1.3 metres east to west and 1 metre north to south, descends 1.75 metres into the earth; a modest opening that belies the historical significance of what lies beneath.

The souterrain sits on a gentle ridge in farmland that slopes towards the southeast, its location carefully chosen by those who constructed it centuries ago. These subterranean passages, found throughout Ireland, were typically built between the early medieval period and the 12th century, serving local communities as secure storage spaces for food and valuables, or as hiding places during raids. The Annagh example, whilst now filled in, represents one of many such structures documented across County Donegal during archaeological surveys.

Though this particular souterrain cannot be explored, its presence serves as a reminder of the ingenious defensive and practical strategies employed by Ireland’s medieval inhabitants. The Archaeological Survey of County Donegal, conducted in 1983, catalogued this and numerous other field antiquities across the county, preserving knowledge of these hidden monuments that might otherwise be forgotten. Even in its current state, the site continues to tell a story of survival, community, and the enduring marks left by those who shaped this landscape long before modern times.