The Grianan of Aileach is a prehistoric hillfort built of dry stone on a hill called Greenan Mountain, that rises to a height of about 800 feet some about 8km from Derry city. The enclosure is surrounded by beautiful views of Lough Swilly and Lough Foyle. The main structure of An Grianan is a stone ringfort, thought to have been built around 600 AD by the Northern Uí...
