What makes it quietly remarkable is its proximity to Magh Adhair, the inauguration site of the Dál Cais, the dynasty that produced Brian Boru. The enclosure lies only forty-five metres from that ceremonial mound, close enough that the two features almost certainly formed part of the same complex of activity in the early medieval period.

The enclosure is defined by a low bank and shares a boundary with a ringfort immediately to its north-east, the two structures conjoined rather than simply adjacent. Ringforts, roughly circular or oval enclosures bounded by earthen banks and ditches, were the most common form of rural settlement in early medieval Ireland, used variously as farmsteads, defended enclosures, or high-status residences. The fact that this smaller, D-shaped enclosure attaches directly to one, rather than standing alone, suggests it may have served a specialist or subsidiary function. To the north of the pair, ancient field boundaries run east to west, hinting at a wider pattern of organised land use in the area. Taken together, the enclosure, the ringfort, the field systems, and the nearby inauguration mound form a concentration of early medieval features that points to Toonagh as a place of some local consequence, even if no documentary record names it directly.