This is a rath, the commonest type of ringfort found across Ireland, built by early medieval farming families as a defended homestead. The outer dimensions here are modest, roughly 31 metres north to south and 35 metres east to west, but the double-bank arrangement gives it a more elaborate profile than many of its kind. Between the two banks runs a fosse, a defensive ditch, and the whole ensemble represents a pattern of enclosure that was repeated across the Irish countryside from around the fifth to the twelfth century.

The site's measurements tell a quiet story of partial survival. The inner bank stands to a height of just 0.6 metres, and it carries three gaps, one to the north-northeast, a wider one to the northeast measuring 6.4 metres across, and a narrower break to the southeast at 1.7 metres wide. These openings may represent original entranceways or later breaches in the earthwork. The fosse survives along the arc from northeast to west, accompanied on its outer edge by a low external bank that runs from the southeast around to the southwest, standing at roughly 0.3 metres. In the interior, low mounds of earth and stone suggest the buried remains of whatever structures once stood within. These might relate to the original settlement, to later use of the space, or simply to the slow accumulation of collapsed material over centuries. The townland name, Caher, itself derives from the Irish cathair, a word for a stone fort or enclosure, which suggests that this corner of Mayo had a long association with defended or enclosed settlements before any written record began.