Low rises to the north, east, and south are the only physical hints that something deliberate once stood here, and without knowing what to look for, most people would walk straight past it.

A rath is a ringfort, the most common type of early medieval settlement in Ireland, typically consisting of a circular earthen bank enclosing a farmstead or homestead. At Knocknamona, the enclosure measured approximately thirty metres in diameter. By the time the Ordnance Survey mapped the area in 1842, it appeared on the six-inch sheet as a hachured roughly circular feature, the standard cartographic shorthand of the period for an earthen enclosure. That map record is now more informative than the ground itself, because at some point between the mid-nineteenth century and the present, the site was levelled, most likely through agricultural improvement. The bank and its interior were reduced to the gentle undulations that survive today.