Mary FitzMaurice, 4th Countess of Orkney (née O'Brien; 4 September 1755 – 30 December 1831)[1] was a Scottish peer, the only surviving child of Murrough O'Brien, 1st Marquess of Thomond and Mary O'Brien, 3rd Countess of Orkney.
Thomas FitzMaurice, younger brother of the 1st Marquess of Lansdowne, on 21 December 1777.
Their son, born in 1778, was John FitzMaurice, Viscount Kirkwall (who was the father of the 5th Earl of Orkney, Thomas John Hamilton FitzMaurice).
[2] Her husband died in 1793 with the Countess retaining possession of Cliveden, the family seat of the Earls of Orkney, now owned by the National Trust.
This Orcadian biographical article is a stub.