As Col. William did not marry until the age of 52, he died without issue. The estate passed to his brother David Conyngham who also died childless. As a result, the estate passed to the son of their sister Ann who had married Clotworthy Lenox of Derry, grandson of James Lenox, Alderman of Derry (Mayor of Derry 1693 and 1697), remembered as one of the leaders of the Siege of Derry and the city's Member of Parliament 1703–1713. Col. George Lenox, upon inheriting the estate, adopted the name Lenox-Conyngham and his descendants lived in the house until 1957. George served under Castlereagh in the Irish Volunteers but, after being betrayed by Castlereagh, resigned his commission in disgrace in 1816. As a result of this, combined with his depressive nature, he committed suicide later that year. His 2nd wife Olivia (4th daughter of William Irvine of Castle Irvine, Co. Fermanagh) is said to haunt the house to this day and is reputed to be the best documented ghost in Ireland. George Lenox-Conyngham married as his first wife Jane Hamilton of Castlefin, by whom he had a son and heir William Lenox-Conyngham. Jane's mother was Jean Hamilton, daughter of John Hamilton of Brown Hall Co. Donegal; Jean married John Hamilton of Castlefin Co. Donegal, and after his death married George Lenox-Conyngham's uncle William Conyngham.