Ringfort (Rath), Killycrone, Co. Cavan

What survives is a rath, the most common type of early medieval Irish ringfort, essentially a circular area of raised ground enclosed by an earthen bank and an outer ditch, known as a fosse, that would once have defined the boundary of a farming household. At Killycrone the interior diameter runs to approximately 21.3 metres, which places it at the smaller end of the scale for such enclosures, suggesting a single-family settlement rather than anything more substantial.

The site shows the uneven fate typical of earthworks that have had to compete with farming for centuries. The earthen bank remains quite substantial along the south-south-east to south-south-west arc, but has been worn down considerably elsewhere. The fosse, which would originally have run around the full perimeter, has been filled in across the south-east, west, and northern stretches, and in places replaced by a modern drainage trench. That kind of substitution is common in Cavan and across the Irish midlands, where farmers have long adapted ancient ditches for practical use rather than removing them altogether. A break in the surviving bank at the north-north-west is thought to mark the original entrance, the point where residents and livestock would have passed in and out of the enclosure during the early medieval period, roughly the fifth to twelfth centuries.