The one at Ahawilk, in County Limerick, follows that convention well enough, but attached to its south-eastern side is something less expected: a rectangular annex, walled and ditched in its own right, joined directly to the main enclosure as though added as an afterthought, or perhaps always part of a more deliberate plan.

A rath, to use the Irish term, is an earthen ringfort, typically dating from the early medieval period, roughly 500 to 1000 AD, and built as a farmstead enclosure for a family and their livestock. The example at Ahawilk sits in level pasture and is modest in scale, the circular area measuring 23 metres in diameter. It is defined by an earthen bank, standing about 15 centimetres above the interior ground level and 35 centimetres above the exterior, with a fosse, that is a surrounding ditch, some 1.2 metres wide running outside it. The rectangular annex conjoined to its south-eastern arc measures roughly 21 metres east to west and just over 15 metres north to south, enclosed by its own earthen bank and a narrower fosse approximately one metre across. Annexes of this kind are known from other Irish ringforts and may have served as stock enclosures or working yards, though the specific function here is not recorded. The site was compiled for the archaeological record by Denis Power.

The earthworks are low-lying and could easily be mistaken for ordinary field undulations, particularly in summer when pasture grass is thick. The interior height of the banks is only 15 centimetres above the enclosed ground, so what is visible from a distance is subtle rather than dramatic. The external faces are slightly more pronounced, which gives the best indication of the fosse line when approaching. The site lies in farmland, so access would require landowner permission. Those with an interest in the form should look for the junction point where the curved bank of the circular enclosure meets the straight bank of the annex on the south-eastern arc, that conjunction is where the unusual geometry of the site becomes clearest.