It is large enough to suggest real ambition on the part of whoever raised it, measuring around 53 metres east to west and 48.5 metres north to south, yet enough of it has crumbled or been cut away that it takes some concentration to read the full shape from the ground.

The site is a rath, the Irish term for a ringfort, which was the standard form of enclosed rural settlement in early medieval Ireland, typically dating from somewhere between the sixth and tenth centuries. Most were the farmsteads of single family groups, their earthen banks and ditches marking off a domestic space rather than a military one. This example at Cloonascragh was originally defined by two concentric banks with a fosse, or ditch, running between them, a double-banked arrangement that would have indicated a certain degree of status among the people who built it. What survives today is partial: the inner bank is traceable from the south-west around to the north-west, and again from the north-east to the south-east, but elsewhere only a scarp, a sloped edge in the ground, hints at where the enclosure once stood. Of the outer bank, only the stretch between the south-east and south-west remains visible. The breaches scattered through what is left appear to be modern damage rather than ancient collapse, and a field bank, likely laid out during post-medieval land division, cuts directly across the monument at the south-west, further complicating its outline.