Measuring roughly twenty metres north to south and twenty-one metres east to west, the enclosure is defined partly by a low bank of earth and stone and partly by a natural scarp, the ground simply dropping away where the bank element gives out. It is small, unspectacular, and precisely the kind of place that centuries of agricultural use have reduced to near-invisibility.

This is a rath, the Irish term for a ringfort, a type of enclosed farmstead common across Ireland from the early medieval period, roughly between the fifth and twelfth centuries. Tens of thousands were built, and yet each one represents a household, a family's decision about where to live and how to defend their livestock and their lives. At Carrowcashel, the builders had to contend with an awkward hillside: the south-west portion of the interior has been deliberately raised to level out the slope, a small but telling piece of practical engineering. The bank itself is low, its internal height around thirty centimetres and external height around forty, suggesting that whatever defensive function it once served was modest. A steep west-facing slope complicates the outer edge to the south-west and north-east, where the ground breaks sharply below the bank's base. In the north-east quadrant there is a possible souterrain, an underground stone-lined passage or chamber that in early medieval Ireland was used for storage or concealment, though its precise extent and condition remain uncertain. The northern half of the enclosure has been damaged by cattle poaching, the repeated churning of hooves softening and obscuring features that might otherwise have survived.