This one, however, sits just 45 metres from Magh Adhair, the ancient inauguration site of the Dál Cais, the dynasty that produced Brian Boru. That proximity is what makes a modest ridge of earth and stone, nowhere taller than half a metre, quietly worth pausing over.

The boundary itself is built from earth and stone, running roughly east to west for around 90 metres before turning southeast for a further 30 metres, with a second arm extending northwest for approximately 60 metres from that junction. It sits in a low-lying area at the northwestern edge of what the landscape forms into a natural bowl, and lies about 7 metres north of a ringfort and an associated enclosure. A ringfort, to give the term its due, is a circular enclosed settlement, typically of early medieval date, defined by one or more earthen banks. The combination here, a field boundary in close relation to a ringfort and an enclosure, all gathered around the ceremonial mound at Magh Adhair, suggests this corner of Toonagh was organised and occupied with some deliberateness. Whether the boundary is contemporary with the ringfort or represents a later reorganisation of the land around these older monuments is not certain, but its alignment and dimensions, between 2.5 and 3.5 metres wide, point to something more considered than a casual field division.