This stone is called Cuchulainn's Stone and is located in a field just outside Knockbridge, in rural north county Louth.
Having finally succumbed to his enemies and in a last desperate attempt to keep the morale of his army intact and fool his foes, Cuchulainn, although mortally wounded, strapped himself against this stone as he was dying so that his enemies might think he was still alive.
Only when a raven (The Morrigan) landed on his shoulder did they know that Cuchulainn was dead.