What remains at Annaghkeen sits on a low hill in scrubland that floods periodically, which gives the site an oddly provisional quality, as though it has been quietly negotiating with the landscape for centuries.

The structure is a cashel, a type of ringfort defined by a drystone wall rather than the earthen banks more commonly associated with these early medieval enclosures. At roughly 32 metres in diameter, the surviving arc of wall runs from the south-west around through the north to the north-east, built from massive limestone blocks laid without mortar in the dry-stone tradition. Where the boreen, a narrow rural track, crosses the monument at either end of that arc, the wall disappears, and no surface trace survives to the south-east of the road at all. Whether that missing section was dismantled to allow the lane's construction, or simply robbed out over generations for building material elsewhere, is not recorded. The limestone itself is characteristic of the north Galway landscape, where the underlying geology makes such blocks readily available and long-used as building material.

The flooding scrubland setting is worth bearing in mind for anyone hoping to get close. The low hill offers just enough elevation to have made the site defensible or at least visually commanding in its original context, but the surrounding ground can be waterlogged, and the bisecting boreen is the most obvious point of orientation when trying to locate what remains of the arc of wall.