To walk past it without knowing what you were looking at would be entirely understandable. But the slight D-shaped swell in the grass, roughly 34 metres across at its greatest extent, is the levelled ghost of an early medieval enclosure that was already old when the first Ordnance Survey mappers recorded it in 1842.

Ringforts, known in Irish as raths when they are earthen enclosures rather than stone-built cashels, were the standard farmstead type across Ireland from roughly the early centuries AD through to the end of the first millennium. They varied considerably in scale, but most were enclosed by one or more circular earthen banks with an external ditch, and the interior would have contained a house and ancillary structures for a farming family of some local standing. The Shinanagh example, as it appeared on the 1842 Ordnance Survey six-inch map, was a roughly circular enclosure of around 30 metres in diameter, shown with the hatched markings cartographers used for earthworks. By the time modern surveyors examined the site, it had been substantially levelled, its northwest side cut through by a field boundary that has since become a permanent feature of the landscape. A barely perceptible trace of the original outer ditch, the fosse, remains faintly legible to the east, visible only as a slight depression in the right conditions of light and season.