Newcastle was the home of Andrew Clarke O'Malley, son of George O'Malley of Spencer Park. Following the death of Andrew's son, Owen Bingham Manners O'Malley, in 1886, Newcastle became the property of his sister, Elizabeth Brewster. Count Manus O'Donel, a Major General in the Austrian Service, lived at Newcastle in the late 18th century. In 1786 Wilson refers to it as the seat of General O'Donnell. Occupied by David Ruttledge in 1814 and by Jacob Beckett at the beginning of the 20th century. Only a portion of the original building is now extant.