This one is visible only from the air, and only under the right conditions. At Carrigleagh in north County Cork, a circular enclosure roughly thirty metres across has left no trace that a walker would notice underfoot. What survives is a cropmark, the faint differential in how crops grow over buried features, in this case the filled-in fosse, or defensive ditch, that once ringed the enclosure. The outline only became legible in an aerial photograph taken in July 1989.

The photograph revealed not just the circular form but a possible rectangular annexe attached to its northern side, a detail that complicates any simple reading of the site. Circular enclosures of this kind are found widely across Ireland and are broadly associated with the early medieval period, though they range considerably in date and function, from enclosed farmsteads to sites with ritual significance. The fosse itself, a rock-cut or earth-cut ditch that would originally have defined and defended the interior, is the only structural element identified here. The site sits within a wider field system, suggesting that whatever its original purpose, the landscape around it was organised and worked for a long period. Without excavation, the relationship between the enclosure and that field system remains open.