Howth Portal Tomb - Aideen's Grave

Howth Portal Tomb is also known as Aideen's Grave. It is located in the wooded area behind the Deerpark Hotel in the grounds of Howth Castle. Howth Castle and estate is located just outside of the village of Howth, County Dublin Ireland (Irish: Binn Éadair, Contae Bhaile Átha Cliath, Éire). The dolmen has a very large capstone estimated at about 75 tons. Probably contributing to the collapse of the supporting stones. Monuments of this type are estimated to date to the Neolithic period which began in Ireland in about 3000 BC. 

The alternative name of Aideen's Grave is related to an Irish legend involving Aideen wife of Oscar who was the son of Oisin and grandson of the legendary hunter warrior Fionn mac Cumhaill. When Oscar died at the Battle of Gabhra, Aideen died of grief and shock. The story then has it that Oscar’s father Oisin had her buried at Howth and had the Dolmen constructed as a memorial to her.