It is, in fact, the remnant of a rath, the Irish term for a ringfort, the type of enclosed farmstead that was once the most common form of rural settlement across early medieval Ireland. Thousands were built between roughly the sixth and tenth centuries, and though they varied considerably in size and elaboration, all shared the same basic principle: a circular or oval area of living and farming space enclosed by one or more earthen banks, with a ditch outside.

The Cahercrea example measures approximately forty metres on its north-south axis and thirty metres east-west, placing it within the middling range for such monuments. What defines it now is a single bank, and even that has suffered. Field boundaries cut through the monument at both the north-west and north-east, the kind of incremental agricultural reorganisation that has quietly damaged or erased so many similar sites across the country over the centuries. The east-facing orientation of the slope would have made it a practical choice for early farmers; a slope opening to the east catches morning light and tends to offer some shelter from the prevailing westerly weather that sweeps across this part of Connacht.