The trace is so faint that a casual walker could cross it without noticing anything at all, yet what remains is the ghost of a rath, a type of circular earthwork enclosure that was the standard form of rural settlement across Ireland throughout the early medieval period, roughly between the fifth and twelfth centuries.

Raths were constructed by enclosing a living area with one or more earthen banks and ditches, creating a boundary that offered both a degree of physical protection and a visible mark of status in the landscape. At Knockaun, the circular outline measures approximately thirty metres in diameter, and today it survives only as a low scarp, a slight drop in the ground surface where the original bank has all but dissolved back into the earth. Centuries of agricultural activity, ploughing, and grazing have done their slow work, leaving almost nothing upstanding. The site sits within undulating pastureland, the kind of terrain that has been in more or less continuous use since long before anyone thought to record what lay beneath it.