It is a rath, the Irish term for a ringfort, the kind of enclosed farmstead that tens of thousands of early medieval families once built across the country, typically between the sixth and tenth centuries. What makes this one worth pausing over is the way it has settled into the hillside: rather than announcing itself, it has subsided into the landscape over many centuries until its defining bank is little more than a broad, low swell in the grass.

The enclosure measures about twenty metres in diameter, defined by a bank roughly four and a half metres wide that now stands barely a tenth of a metre above the interior on its inner face, and only four tenths of a metre on the outer. At its most legible, on the south-southwest to northeast arc, it survives as a scarp dropping about a metre, blending into the natural slope of the hill rather than standing apart from it. Outside the bank, a shallow fosse, the ditch that would once have reinforced the enclosure's boundary, is still detectable as a gentle depression, most visible on the northeast to southwest side. The site occupies a natural terrace on the north-northwest-facing slope of what the 1929 Ordnance Survey six-inch map names Barrett's Hill, a steep-sided drumlin ridge. The southern slope of the same hill descends to a shoreline inlet of Clew Bay about three hundred metres away, and though that view is blocked by the rising ground immediately to the south, the position opens westward across a valley of low-lying land, with Croagh Patrick visible across the bay to the southwest. A larger ridge rises sharply to the north, with only a narrow pass between it and Barrett's Hill. Thirty metres upslope to the south, on the same hill, a second enclosure survives, suggesting that this corner of the demesne once held a small concentration of activity, whatever its precise nature or date.