The Crom Estate is a nature reserve located in the south of County Fermanagh, Northern Ireland, along the shores of Upper Lough Erne. It is one of three estates owned and managed by the National Trust in County Fermanagh, the others being Florence Court and Castle Coole mansions. The estate comprises 1,350 acres (5.5 km2), composed primarily of riparian forest. Some trees are so ancient that physical access is restricted.