This is a rath, a type of enclosed farmstead typical of early medieval Ireland, usually dating to somewhere between the sixth and twelfth centuries. Constructed from earth rather than stone, a rath consisted of one or more circular banks with a ditch, known as a fosse, dug between them to create a defensible or at least demarcated enclosure for a farming family and their livestock.

The Traskernagh example is a modest one, roughly twenty-six metres in diameter, and two concentric banks once defined its perimeter. The inner bank survives with a base width of five metres, though it has weathered considerably over the centuries, standing only about 1.7 metres on its outer face. The fosse between the banks, about 1.4 metres wide, is still traceable around the full circuit. The outer bank has fared less well. A field boundary was built directly on top of it at some point, and along the northern sector the original earthwork has been absorbed so completely into the modern landscape that no surface trace remains. It is a common fate for sites like this, where generations of farming activity gradually reassign old features to new practical purposes, field walls consuming the evidence of earlier ones.