A cashel, which is the term used for a ringfort built from stone rather than earth and timber, once sat in the open landscape here in an oval roughly 25 metres north to south and 35 metres east to west. Today, the site is so thoroughly consumed by blackthorn and brambles that only a small fragment of the original wall breaks through the tangle at the northern edge, a section about 3.7 metres wide and barely half a metre high on either face. The rest has been swallowed whole.

The enclosure appears on the 1838 Ordnance Survey six-inch map, already described as an oval shape with its long axis running north to south, and it was still being mapped in the same terms by 1913. Ringforts of this kind were typically built during the early medieval period, roughly between the fifth and twelfth centuries, and served as enclosed farmsteads for individual family groups. The cashel at Crockacullion fits that tradition, though whatever domestic or agricultural life once took place inside its walls has left no visible trace above the current tangle of vegetation. The ground has been in pasture, and the enclosure has been left to whatever slow negotiation exists between old stonework and determined scrub.