The enclosure measures roughly 12.4 metres north to south and 13.2 metres east to west, enclosed by an earthen bank that still stands to about 1.1 metres in height. It is modest in scale, easily mistaken for a natural rise in the ground, yet its geometry is deliberate and its survival, in agricultural land that has been worked for centuries, is quietly remarkable.

Circular earthen enclosures of this kind are a familiar if not fully understood feature of the Irish countryside. They are broadly referred to as ringforts when associated with early medieval settlement, typically dating from roughly the fifth to the twelfth centuries, though many were constructed earlier and the tradition is long-lived. The earthen bank would originally have defined a farmstead or enclosed area of some domestic or agricultural significance, with the raised perimeter serving both as a boundary and, in some interpretations, a modest defensive barrier. What lies within this particular example at Knocknagappul, whether traces of post-holes, hearths, or souterrains (the stone-lined underground passages sometimes associated with such sites), is not recorded, and the pasture that now covers it preserves whatever evidence may remain beneath the surface.