It is a rath, the Irish term for a ringfort, the most common type of monument surviving in the Irish countryside. These enclosures, typically defined by one or more banks and ditches thrown up from earth or stone, were the farmsteads of early medieval Ireland, occupied roughly between the fifth and twelfth centuries. Tens of thousands once existed across the island; a few thousand remain in recognisable form. Most have no interpretive signage, no fencing, no particular fanfare. They are simply there, in fields, on hillsides, at the edges of farms.

Clare is a county unusually well furnished with such remains. The underlying limestone geology, which discourages deep ploughing in many areas, has helped preserve earthworks that would elsewhere have been levelled over centuries of agricultural improvement. Kiltrellig as a place-name has the structure common to many Irish townland names, combining elements that often reference early ecclesiastical or geographical features, though the specific etymology here is not certain. The rath itself would originally have enclosed a family's dwelling, outbuildings, and perhaps livestock pens, with the raised bank serving as much as a statement of status and boundary as a defensive structure. In folk tradition, ringforts across Ireland became strongly associated with the sí, the fairy mounds, and were frequently left untouched by farmers who feared the consequences of disturbing them. That superstition, more than any formal protection, is the reason a great many of them survived at all.