He recorded its local name as Tuam an Gaskaigh, and noted at its floor a feature referred to as the 'giant's grave', a label that tends to attach itself, across Ireland, to ancient stone alignments or megalithic remains whose original purpose had long since been forgotten. What makes this cashel, a type of stone-walled ringfort built without mortar, quietly peculiar is its shape and situation: a roughly D-shaped enclosure, the curved wall to the south, a secondary wall running straight across the hollow like a chord drawn through a circle, and the whole thing oriented so that on a clear day the Aran Islands and a stretch of Galway Bay are visible to the east, while the surrounding landscape offers almost nothing else in the way of prospect.

Westropp measured the main wall at between four and a half and five feet thick, built of large, regularly-laid slabs. Field inspection in 1998 found it still standing to between half a metre and just over a metre in height, with the enclosure measuring roughly 36 metres north to south and 30 metres east to west. Traces of what may be hut structures were identified along the inner face of the perimeter wall at several points, including the ENE, W, and NW. The boulders in the south of the interior, aligned roughly northeast to southwest and once tentatively identified as a megalithic structure, were on inspection considered of uncertain antiquity. Further stone walls abut the outside of the cashel at multiple points, and a separate enclosure lies about 85 metres to the south-southeast, suggesting this was once part of a broader pattern of activity on the hillside rather than an isolated feature. The 1915 Ordnance Survey six-inch map recorded the site using hachures, the cartographic convention for showing a depression or earthwork, though later classification hedged its bets by listing it simply as an enclosure.