Whilst early Ordnance Survey maps from the third edition marked this location as 'Caves', suggesting multiple underground chambers, closer examination reveals a single souterrain with a rather unusual dual entrance system. These ancient underground passages, found throughout Ireland, were typically constructed between the early medieval period and the 12th century, serving as storage spaces, refuges, or perhaps holding ritual significance for the communities that built them.

The southern entrance presents itself as a circular opening, measuring 1.25 metres across and extending 2.25 metres into the earth. The northern entrance, somewhat smaller at 1.5 metres by 0.5 metres, features a particularly fascinating detail; its lintel bears cupmarks on the underside, those enigmatic carved depressions that appear on stones throughout prehistoric Europe and whose purpose remains largely mysterious. These markings might indicate the souterrain held special significance, perhaps marking it as a place of ritual importance or simply serving as territorial markers for those who knew their meaning.

According to archaeological surveys, three chambers are believed to branch off from the main shaft, though the challenging terrain and the structure's current condition make full exploration difficult. The souterrain's construction in such rocky, uneven ground speaks to the determination and skill of its builders, who would have had to work around natural stone formations whilst creating a stable underground structure. Like many of Ireland's souterrains, this one at Glenmakee offers a tangible link to the island's medieval past, when such underground passages dotted the landscape, serving the practical and perhaps spiritual needs of farming communities who called this rugged corner of Donegal home.