Ring of Gullion AONB

The Ring of Gullion is located in County Armagh, Northern Ireland. It measures roughly 26 by 11 miles (42 by 18 km) and comprises some 150 km² defined topographically by the hills of the Ring Dyke.

The formation is a type-example of a Ring Dyke. Which formed during the Tertiary opening of the Atlantic Ocean during the emplacement of the Tertiary Igneous Province.

The Ring Dyke's structure was produced when the active volcano's caldera underwent collapse producing a concentric suite of faults through which magma was able to escape and erupt. The composition of the remainder of the volcano today is dominated by Gabbro and granophyre and is also so site of a noted PGE occurrence.

The area of the Ring of Gullion Area of Outstanding Natural Beauty includes the Mountain Ring and its various slopes, but also there is a deviation to the west to include the famous Dorsey Enclosure. In the west it also includes the valley of the Cully Water and the Umeracam River which separate the hills of the ring dyke from the rolling drumlin landscape extending towards Crossmaglen and Cullyhanna. In the north-west the ring dyke runs through the higher ground of the Fews where it is picked out by sharp rocky hills with distinctive heath vegetation (which is the derivation of The Fews name). To the east its boundary is the Newry Canal and the Newry River flowing towards Carlingford Lough under the brow of Anglesey and Flagstaff Mountains.