The example recorded at Cashel in County Mayo is one such site, a rath, which is the Irish term for a ringfort defined by an earthen bank rather than stone walling. These were the farmsteads of early medieval Ireland, typically dating from roughly the fifth to the twelfth centuries, enclosing a family's dwelling and outbuildings within a circular or oval embankment, sometimes accompanied by a fosse, or external ditch. They were not primarily military structures, though the enclosure would have offered a degree of protection for livestock against wolves and cattle raiders.

Raths of this kind are particularly associated with the more fertile lowland areas, though Mayo's western parishes contain a number of them, often in townlands whose Gaelic names preserve older layers of settlement history. The townland name Cashel itself is worth noting: it derives from the Irish "caiseal", meaning a stone fort or enclosure, which suggests the area may have had a longer tradition of enclosed settlement before the earthwork rath was constructed. Whether the name refers to this monument or to some other, now-lost structure in the vicinity is not possible to say with certainty from what survives.

Beyond its classification and location, little detailed information about this particular site is currently available in the public domain. What can be said is that ringforts of this type reward a careful look in person. The earthen banks, where they survive intact, can still stand a metre or two in height, and the interior space, once you recognise it for what it is, tends to have a particular quality of enclosure that aerial photographs never quite capture.