The extensive property at Newcastle was originally the seat of the Harman family, which came into the King family through marriage. In 1837 Lewis referred to it as the seat of the Dowager Countess of Ross. At the time of Griffiths Valuation in the 1850s it was the seat of Laurence King-Harman and was valued at £90. In 1906 it was owned by Col. W.H. King-Harman. It remained in the family until the twentieth century when it was sold to an order of religious sisters. In the later 20th century and again more recently it has functioned as a hotel. A Center Parcs resort is now located in an area of the former demesne.
Newcastle House [Ballymahon] (National Inventory of Architectural Heritage)
