When the antiquarian T. J. Westropp visited in the years around 1914 to 1916, he recorded that the rampart across the promontory's neck had stood, just twelve years before his arrival, as a straight, massive wall of large, thin dry-stone slabs approximately six feet high, running between 161 and 164 feet in length and between 18 and 21 feet thick. He also noted a lintelled, stone-lined entrance through the wall, a carefully finished threshold that implied this was once a place of some deliberate occupation or defence. That level of preservation is now gone.

A promontory fort of this kind uses natural geography as its primary defence, with the sea doing much of the work on three sides and a constructed barrier, typically a wall or earthen bank with an external ditch, sealing off the landward approach. At Gortacrossig, the wall has since collapsed to a height of roughly 1.1 metres and a width of around 6 metres, though stone facing is still visible on both sides of the rubble. The entrance Westropp described has fallen too, surviving only as a grass-covered gap about 2 metres wide in the bank. Outside the bank runs a fosse, that is, a ditch dug to strengthen the defensive line, measuring some 6.6 metres wide and 1.35 metres deep, though a field fence has disturbed it to the west of the entrance. A second, narrower fosse sits inside the bank, with a causeway marking the original approach to the entrance. The interior of the promontory is now overgrown, with rock outcropping through the vegetation in places.

What makes the site quietly affecting is precisely what Westropp's account preserves: the gap between what was there in the early twentieth century and what remains now. His description of a substantial, carefully built dry-stone wall sitting almost complete within recent generations is a reminder of how quickly an unprotected structure on an exposed Atlantic headland can dissolve back into the landscape.