The bank is barely thirty centimetres at its highest, and the surrounding fosse, a shallow ditch dug to reinforce the boundary, drops no more than thirty centimetres below the surrounding field. By any measure, this is a modest earthwork, and yet its near-perfect circularity, roughly 33.8 metres east to west and 33.5 metres north to south, betrays deliberate construction rather than any accident of topography.

This is a rath, the Irish term for a type of ringfort built from earth rather than stone. Ringforts were the most common settlement type in early medieval Ireland, typically dating from roughly the fifth to the twelfth centuries, and serving as enclosed farmsteads for a single family and their livestock. The enclosing bank and ditch were less about serious military defence and more about marking territory, containing animals, and conferring a degree of social status on the occupant. Thousands survive across Ireland in varying states of preservation, though many have been levelled by agriculture over the centuries. The Sunfort example sits on a gentle south-south-east facing slope, a practical orientation that would have offered some shelter and good light, and its interior and bank are now densely overgrown with hawthorn bushes, which have in a quiet way helped preserve the earthwork by discouraging clearance and ploughing around it.