First the enclosure itself was erased, then the very field boundaries that had absorbed its remains were also cleared away, leaving nothing at all for anyone standing there today to read.

The 1838 Ordnance Survey six-inch map, one of the most detailed early records of the Irish landscape, shows an oval enclosure on that modest hillock, measuring roughly 25 metres east to west and somewhere between 30 and 35 metres north to south. Its shape and scale suggest a ringfort, the circular or oval earthen enclosures built across Ireland from the early medieval period onward, typically serving as defended farmsteads for a single family and their livestock. By the time the 1920 edition of the same map series was produced, the enclosure had already been levelled, though its south-western arc had been folded into the local field boundaries, preserved in outline if not in height. Those boundaries have since been removed as well. The hillock remains, but the structure it once carried has been absorbed so completely into the agricultural reworking of the land that there is no visible trace left.

What makes this site quietly interesting is precisely that absence. The 1838 map captures it at one of the last moments it could be recorded, and the gap between that survey and the 1920 edition marks the period when it was lost. The enclosure at Derryfadda is now a place defined entirely by what earlier cartographers noted down rather than by anything a visitor could observe on the ground.