The enclosure at Mullagh is roughly oval in plan, measuring around 35 metres north to south and 40 metres east to west, and enclosed by a broad, earthen-and-stone bank of the kind commonly associated with early medieval settlement in Ireland. These ringfort-type enclosures, built to define a domestic or ceremonial space rather than for any serious military purpose, are scattered across the Irish landscape in their thousands, yet many have quietly disappeared beneath field improvements and changing land use. This one has survived, albeit awkwardly.

By the time the second edition of the Ordnance Survey six-inch map was produced between 1901 and 1905, the bank in the north-western quadrant had already been levelled, suggesting that at least some modification or agricultural clearance had taken place before the twentieth century was well under way. A modern field boundary runs east to west along the southern edge of the monument, abutting the bank there, which is one of the few stretches visible and relatively clear of growth. The rest of the enclosure interior had, at the time it was recorded, become impenetrable with overgrowth, the small trees rooted into the bank itself making the full circuit difficult to trace on foot. The surrounding field, cut for hay, offers a telling contrast: the managed, open pasture stopping abruptly where the old bank begins and the scrub takes over.