That alone sets it apart from the more familiar circular or neatly oval enclosures found elsewhere in the Irish uplands. The wall, originally around two metres wide with an inner and outer facing holding a rubble core, now survives as a low, largely sod-covered bank, barely half a metre high in places. Where the natural rock face was steep enough to deter approach, the builders simply left gaps, letting the geology do the work instead.

The knoll sits on a terrace on a broad east-west spur that projects into the south-western end of Lough Mask, with the county boundary between Mayo and Galway running along the valley below to the south. The interior of the enclosure, roughly 80 metres north to south and 60 metres east to west, is anything but flat; exposed bedrock ridges and hollows cross it in undulating bands, leaving only the southern third as genuinely level ground. Layered over this older structure are traces of later agricultural use. A narrower, more lightly built field wall runs north to south through the eastern half of the interior and clearly post-dates the enclosure, continuing beyond its walls to connect with a wider grid of relict field boundaries on the surrounding terrace. Broad, flat-topped cultivation ridges, the kind associated with intensive tillage in marginal land, run east to west in the level pockets inside the enclosure, and similar ridges appear in the hollow at the north-west. The surrounding field system, much of it recorded on the 1828 Ordnance Survey six-inch map and again on the 1929 edition, appears to be eighteenth or nineteenth century in date, suggesting that long after the enclosure lost whatever original purpose it served, people were still coaxing crops from the few workable strips of earth it contained.

The easiest approach to the enclosure is from the west, where the ground drops away gradually and a clear line of sight opens towards the deep, steep-sided valley of Lough Nafooey. To the east, rising slopes close in the view almost immediately. The enclosure is not signposted and sits in rough upland pasture; the low, grass-covered wall is easy to walk past without registering what it is, which is part of what makes finding it worthwhile.