At 1.85 metres high and relatively slender, the upright sits at the east-north-east of the circuit, tilted slightly so that its top slopes toward the east. It is an odd thing to encounter at the edge of a grassed-over ringfort, and it may not have always stood where it does now.

A cashel is a type of early medieval ringfort defined by a stone wall rather than an earthen bank, and this one is subcircular in plan, measuring roughly 19 metres north to south and 17.6 metres east to west. The outer wall-face is built from large, horizontally laid limestone blocks, though time and gravity have sent some of them spilling outward, particularly at the south and west. The interior sits unusually high, almost level with the top of the surrounding wall. To the north, a modern laneway has cut a clean, straight truncation across the wall over a stretch of about 13 metres, one of those small indignities that farmland regularly inflicts on older structures. The site appears on the Ordnance Survey 25-inch plan of 1897 and again on the 1920 edition of the 6-inch map, where it is labelled Lismoher; Robinson's map of 1977 gives the Irish form, Lios Mothair. The cashel sits within a wider multiperiod field system, and a hut site lies roughly 120 metres to the west-south-west, suggesting this corner of Clare was organised and occupied across several phases of activity.

The tall upright stone is the most puzzling element. The antiquarian Thomas Johnson Westropp, writing in 1915, recorded a ruined doorway at this cashel that faced east, and the dimensions of the upright are close enough to those of a lintel that it may once have formed the top of that entrance. Just to its north, a gap of about one metre in the wall could be the remains of the original doorway itself. Whether the stone fell and was later set upright, or whether it was always positioned as it now appears, is not something the ground has given away.