Once the residence of the Annesley family and the center of their vast estate, Castlewellan Castle is now part of the Castlewellan Historic Demesne, which includes an arboretum and walled garden started by the Annesleys and a forest park and lake open to the public. The castle is used as a Christian conference center and we were part of a conference held there last summer, the reason why we were in Northern Ireland. The castle overlooks a lake with the Mourne Mountains in the distance.