It is the kind of structure that could easily be passed off as a natural arrangement of rock, yet it represents a very deliberate human decision: to build here, on this slope, above this particular stream.

The site is classed as a subcircular hut site, a category that covers a broad span of Irish prehistory and early medieval life. Such structures were typically built by people working or living at a remove from settled lowland communities, whether as seasonal shelters for those moving livestock to summer pastures, or as more permanent dwellings on the upland margins. The walls at Glasnamullen, roughly a metre in thickness, suggest a modest but solid construction, probably using dry-stone technique. The choice of a gentle south-east-facing slope is telling; it would have caught the morning sun and offered some natural shelter from prevailing westerly winds, with the small stream to the south providing a reliable water source close at hand.