Circular in plan, roughly 53 metres north to south and about 50 metres east to west, it survives only as a slight undulation in the grass, three to four metres wide, tracing what was once a bank around its perimeter. It never appeared on any edition of the Ordnance Survey six-inch maps, which suggests it had already been levelled by the time systematic mapping of the Irish countryside began in the nineteenth century. Croagh Patrick sits on the far horizon to the west; a low natural ridge runs to the east. The enclosure reads, from a distance, as nothing at all.

What the ground holds, on closer inspection, is a little more ambiguous. The interior is flat and not noticeably raised above the surrounding pasture, which distinguishes it from the classic raised interior of a rath, the type of circular earthen enclosure, typically of early medieval date, built as a farmstead and defended by one or more banks and ditches. About 230 metres to the east, on the ridge, there is in fact a rath, a separate monument entirely. The Summerhill enclosure belongs to a different, less legible category. In its northern half, there is a shallow circular depression, flat-based, roughly ten to eleven metres across and no more than 0.2 to 0.3 metres deep, whose purpose is not known. A barely traceable linear feature crosses the interior on a roughly north to south axis, most likely the ghost of a levelled field boundary, though it is impossible to be certain. The bank on the western arc merges with a low natural rise, making it difficult to say exactly where the original structure ends and the natural topography begins. The possible entrance, if it is one, lies somewhere between the northeast and east.