What makes it worth pausing over is partly what has been done to it: the fosse, the defensive ditch that once ran around the outside of the enclosing bank, has been backfilled along its north-western to north-eastern arc and recut as field drains elsewhere. The earthwork has, in other words, been quietly cannibalised by agriculture, its ancient geometry pressed into service as land management infrastructure.

This is a rath, a type of ringfort built from earth rather than stone, and one of thousands scattered across Ireland, most dating from the early medieval period roughly between the fifth and twelfth centuries. They functioned primarily as enclosed farmsteads, the bank and fosse providing a degree of security for livestock and a household rather than serving as military fortifications in any serious sense. The Cloonfad example measures approximately 29 metres north to south and 25.3 metres east to west, with an earthen bank varying in width from 2.7 to 3.7 metres. The bank survives better on its eastern side, where its external height reaches 1.9 metres, than on the north, where it barely clears half a metre. There is no visible entrance remaining. A 1972 observation by Gannon recorded the remains of an outer curving bank to the east, which may have been the boundary of an annexe, a secondary enclosure sometimes attached to ringforts for extra storage or animal shelter, but that feature can no longer be seen on the ground.