The feature is a rath, the Irish term for a ringfort, which was typically a circular or subcircular enclosure defined by an earthen bank and an outer ditch, or fosse, used as a defended farmstead during the early medieval period, roughly between 500 and 1000 AD. Tens of thousands of these structures once dotted the Irish countryside, making them among the most common monuments in the country, yet the vast majority have been partially or entirely lost to agriculture and development. This one in Corbally More survives only in part, which is precisely what makes it worth a second look.

The enclosure measures approximately 42 metres from west-north-west to east-south-east and 39 metres from north-north-east to south-south-west, making it a reasonably typical size for a rath. It sits in undulating grassland about 150 metres south of a stream, a placement that would have offered convenient access to water without the risks of a flood-prone site. The defining bank is visible across roughly half the circuit, running from the east-north-east around through the south and on to the north-west. Where the bank has been lost or reduced, a natural or artificial scarp takes over the role of enclosing the space. The outer fosse, the shallow ditch that would originally have reinforced the bank's defensive function, survives along the southern and western sides through to the north-west. Complicating the picture is a later field bank, which has been laid directly over the original rath bank on the north-east to south-south-east arc, effectively cannibalising the older monument and making portions of it harder to read as a coherent whole.