This is a stone ring fort which sits on an exposed hilltop 800 feet above sea level in Innishowen, Co Donegal.
It is thought to have been built in the 6 th or 7 th Century but the site may have been used even before that. That position may have been chosen because of a burial mound which lies to the left of the fort and which could date back to 3000BC Grianan is steeped in myth and legend. One story tells of giants who lie sleeping and who will spring into life to reclaim their land when a certain sacred sword is removed.
St Patrick is said to have visited this site and baptised the local chief Eoghan at a little well nearby which still survives today. The name Eoghan gave rise to the townland name Innishowen.
The fort was the Royal Citadel of the O’Neills from the 5 th Century to the 12 th Century.
The original ring fort was destroyed by Murtagh O’Brien, the King of Munster, in 1101 when he ordered his troops to each carry away a stone and leave nothing for anyone else to use.
Restoration was carried out in 1870 by Dr Walter Bernard.