Mary FitzMaurice, 4th Countess of Orkney was a Scottish peer, the only surviving child of Murrough O'Brien, 1st Marquess of Thomond and Mary O'Brien, 3rd Countess of Orkney.
Mary FitzMaurice, 4th Countess of Orkney was a Scottish peer, the only surviving child of Murrough O'Brien, 1st Marquess of Thomond and Mary O'Brien, 3rd Countess of Orkney.