This is a rath, the most common type of monument in the Irish landscape, a circular enclosure defined by one or more earthen banks and ditches, built to protect a family's home, livestock, and grain stores. Thousands survive across the country, but each one occupies its own particular ground, and the choice of this hillside above the bay was clearly deliberate.

The enclosure at Ardgehane measures roughly thirty metres across its longest axis, an average size for a single-family rath. The defining bank still stands to about 0.8 metres on the western and north-western arc, accompanied by an external fosse, a ditch running outside the bank, cut to about a metre deep. Around the north-north-west to west-south-west section, the bank has been largely levelled over the centuries, surviving only as a faint scarp just twenty centimetres high, the kind of feature that becomes visible only when low sunlight rakes across the field. Together, these earthworks once formed a continuous defensive ring, and the position chosen for them is telling: the site commands an extensive view southward across Clonakilty Bay, suggesting that whoever built here valued both the agricultural potential of the rolling pasture and a clear sightline over approaching water.