Locally it has long been called Hernon's Cahir, a name recorded as far back as 1914, and that local name is doing useful work: "cahir" is an Anglicisation of the Irish "cathair", meaning a stone fort or cashel, and it places this structure within a tradition of early medieval enclosures built not from earthen banks but from drystone walling.

A cashel is essentially a ringfort constructed in stone rather than earth and timber, and they are particularly associated with the west of Ireland where building stone is plentiful and topsoil thin. This example measures around 37 metres in diameter, with the defining wall still traceable around much of its circuit. The northern arc through to the south-east has been heavily obscured by field-clearance rubble, the kind of accumulation that happens over generations as farmers move stones off cultivable ground and deposit them against any convenient existing structure. A 2-metre entrance gap survives at the north. The result is a site that reads as poorly preserved in any formal sense, yet retains enough integrity to convey the scale and intention of whoever originally enclosed this hillside ground, likely sometime in the early medieval period.