The 1842 Ordnance Survey six-inch map recorded it clearly, rendered in the hachured lines cartographers used to indicate an enclosed earthen bank, measuring roughly 55 metres on its north-east to south-west axis and about 45 metres across. Today the outline is harder to read. A field boundary cuts through it off-centre to the west, and around 1980 the portion to the east of that boundary was levelled off, erasing whatever remained of the bank and fosse on that side. A fosse is simply a ditch, typically dug alongside an enclosure bank, with the excavated earth thrown inward or outward to build up the rampart. Local knowledge suggests there was already little to see on the eastern half before the levelling, which means the damage may have been as much a tidy-up of something already diminished as an act of outright destruction.

Enclosures of this kind are among the most common archaeological features in the Irish landscape, and among the least understood in terms of individual histories. They range in date from the prehistoric period through to the early medieval, and their purposes vary accordingly, from settlement to ritual to agricultural use. Without excavation, the Broghill enclosure cannot be precisely dated or interpreted. What the 1842 map preserves is a moment when the feature was still coherent enough to be surveyed and drawn with confidence, an oval earthwork sitting in farmland that had already been worked for generations. The western portion, still visible as a low and irregular rise, is what remains of that earlier coherence.