This well-preserved sub-circular earthwork in County Clare carries a name derived from the Irish word mothair, a local toponym applied to square or rectangular forts. The site itself is neither square nor rectangular, and the slight mismatch between name and form is one of its quieter curiosities. What survives is a substantial enclosure, roughly 53 metres east to west and nearly 51 metres north to south, defined by an earthen bank up to two metres high with an external fosse, a defensive ditch, running around its outer edge.

The fort appears on the Ordnance Survey six-inch maps of both 1842 and 1915, named 'Mortyclogh fort', and again on Robinson's 1977 map as 'Lios Mothair Tí Cloch', confirming a long cartographic record. The bank retains inner facing-stones along its eastern and southern arc, though on the western and northern sides the stonework has slipped and the structure has softened into the slope. A stone-faced entrance gap, about 3.7 metres wide, sits just east of south, but whatever causeway once carried people across the fosse at this point has gone, most likely worn away by tractors that began using the fosse itself as a convenient passage around the site. Modern cattle gaps cut the bank at three further points. Beneath the gently sloping interior lies a souterrain, an underground stone-lined passage of the kind commonly associated with early medieval settlement in Ireland, positioned roughly 18 metres northeast of centre, though it is currently inaccessible. Around 100 metres to the northeast, a graveyard and a second ringfort occupy the same stretch of ground, making this a small cluster of early features sitting close together on an otherwise ordinary Co. Clare hillside.