This one in Carrowcrom, County Mayo, barely clears the ground. What survives is a roughly circular raised area, measuring about 14.5 metres north to south and 15.5 metres east to west, defined by a partly levelled earthen scarp that reaches only 0.6 metres in height at its tallest point on the southern side. A slightly raised internal rim persists in places, and a low, poorly defined break in the scarp to the southeast may mark where an entrance once stood. It sits on a gentle rise in pasture, with a stream running fifty to sixty metres to the east and open, rolling terrain visible in most directions, though rising ground to the northeast and southwest closes off the longer views somewhat.

A rath is an early medieval enclosed farmstead, typically defined by one or more earthen banks and ditches, and representing the ordinary domestic world of rural Irish life between roughly the fifth and twelfth centuries. This one is a modest example even by the standards of that tradition, its diameter placing it at the lower end of the known size range for such enclosures. What makes its situation stranger still is that it does not appear on the Ordnance Survey six-inch map of 1838, the great baseline survey of nineteenth-century Ireland, but does show up on the 1922 edition. Whether the feature was simply missed by earlier surveyors, or whether it had become more legible in the landscape by the early twentieth century, is an open question. Forty metres to the north lies another possible rath of similarly small dimensions, which raises the thought that this quiet corner of Mayo may once have supported a cluster of small, neighbouring farmsteads, each just visible from the other.