The result is a rath, the most common type of early medieval settlement monument in Ireland, a roughly circular enclosure defined by one or more earthen banks and, originally, a corresponding ditch. This one survives as a raised circular area just under twenty-nine metres in diameter, with an earthen bank still standing to a height of around 1.4 metres along its western to southern arc.

Raths of this kind were typically the enclosed farmsteads of prosperous farming families during the early medieval period, roughly the fifth to the twelfth centuries. The bank and its accompanying ditch would have provided a degree of security for livestock as much as for the inhabitants. Inside, timber buildings have long since vanished, leaving only the earthwork itself as evidence of the life once conducted there. The example at Knocknagoun sits in what is now pasture, which is in some ways fortunate: agricultural land tends to be kinder to earthworks than ploughed ground, where banks are gradually levelled over generations of cultivation. That said, a field boundary has already caused some damage to the south-western section of the bank, a reminder of how incrementally these monuments are worn away by the ordinary business of farming.