It is a rath, the Irish term for a ringfort, a type of enclosed farmstead built and used throughout early medieval Ireland, roughly between the fifth and twelfth centuries. Most were the homes of farming families, their circular banks and ditches marking out a defended domestic space rather than a military fortification. This one measures thirty-two metres in diameter, and while its condition is described as fair, enough survives to read the original form.

The enclosure is defined by a bank and an external fosse, that is, a ditch running around the outside of the bank. At the north-west, the character of the boundary changes slightly: here a scarp, a natural or cut slope in the ground, takes over from the bank as the main enclosing element, and it is only at this section that the fosse remains visible. The rest of the ditch has been filled or worn away over the centuries, leaving the north-west arc as the most legible part of the original design. Some hundred metres to the north-east, a separate earthwork has been recorded, suggesting that this corner of Clooncannon was a more active landscape in earlier periods than the present quiet fields might suggest.