The rath at Coad is a ringfort, the kind of enclosed farmstead that tens of thousands of early medieval Irish families built and lived within, typically between the seventh and twelfth centuries. Most are roughly circular, defined by a raised bank and internal ditch. This one, however, confounds the usual pattern in a small but telling way: its outline is not quite a circle but a subrectangle, a shape that sets it slightly apart from the common form.

Ordnance Survey mapmakers recorded it as a circular feature on both the 1842 and 1920 editions of the six-inch map, but the more detailed 25-inch plan of 1897 captures a subrectangular outline more faithfully. The enclosure measures roughly 23.6 metres west-northwest to east-southeast and 21.1 metres north-northeast to south-southwest on the interior, with an enclosing bank between 3.7 and 5.8 metres wide, still just visible above the surrounding ground. What survives today is modest, the bank rising only 0.3 to 0.6 metres externally, but enough to read in the landscape. A grass-covered bank may extend outward from the northwest corner, though part of it appears to have been cut by the garden of a modern house. The northeast corner, meanwhile, has been partly overlaid by a modern field boundary. Just to the west of the rath, a mid-nineteenth-century racecourse once ran north to south, a detail that places this quietly eroding earthwork in unexpected company, an ancient enclosure beside a Victorian leisure ground, both now largely returned to pasture.