Mount Stewart is a 19th-century house and garden in County Down, Northern Ireland, owned by the National Trust. Situated on the east shore of Strangford Lough, a few miles outside the town of Newtownards and near Greyabbey, it was the Irish seat of the Vane-Tempest-Stewart family, Marquesses of Londonderry. The house and its contents reflect the history of the Vane-Tempest-Stewart family, who played a leading role in British and Irish social and political life.
