The site at Annaghervy is the kind of place that rewards attention: a raised, slightly dished platform roughly 36 metres across, enclosed by an overgrown scarp that still stands somewhere between one and a half and two metres high. A faint outer fosse, the term for a defensive ditch, betrays itself only as a band of unusually lush vegetation, the kind of subtle signal that archaeologists have learned to read in Irish fields.

Drumlins, the smooth oval hills formed from glacial deposits that give County Monaghan much of its characteristic bumpy terrain, were frequently chosen as the foundations for early Irish ringforts. The elevated position offered both a commanding view of the surrounding countryside and a natural contribution to the defences. A ringfort typically consisted of a raised interior enclosed by one or more earthen banks and ditches, and served as a farmstead or settlement, most commonly during the early medieval period. At Annaghervy, that basic form is still legible despite the encroachment of vegetation, the circular geometry intact even if the details have blurred over the centuries. The dished quality of the interior surface, slightly lower at the centre than at the edges, is a feature sometimes associated with long use and the gradual compaction of an enclosed space.