Rather than the familiar complete circle of bank and ditch that defines a rath, this enclosure is C-shaped, open to the north-west through a gap roughly three metres wide, and it sits pressed against the north-western flank of a neighbouring bivallate ringfort as though the two were always meant to be read together.

A rath is an early medieval enclosure, typically dating from roughly the fifth to the twelfth century, formed by one or more banks of earth thrown up around a farmstead or settlement. A bivallate example has two concentric banks rather than one, suggesting a household of some status or a site requiring greater security for livestock. What makes the Sarue enclosure particularly interesting is its relationship to that larger neighbour. The C-shaped earthwork, measuring approximately 21.6 metres north to south and 18.9 metres east to west, is enclosed by an earthen bank rising to about a metre in height, with a shallow external fosse, or ditch, running outside it. Rather than standing alone, it is conjoined with the bivallate ringfort along the arc from north-north-east to south-south-east, meaning the two structures share a boundary and may have functioned as a single complex. Whether the C-shaped enclosure was an annex, a stock pen, or some other adjunct to the main settlement is not recorded, but the physical attachment suggests deliberate planning rather than coincidence.