Cloughoughter Castle in Lough Oughter, County Cavan, Ireland

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No moat required. Cloughoughter Castle, County Cavan, Ireland

Cloughoughter Castle sits on a small island in the middle of Lough Oughter, a huge complex of lakes and waterways in County Cavan in Ireland. Its first stones are thought to have been laid in the early 13th century by the Anglo-Norman de Lacy family, but the O'Reilly clan took possession of the area in 1233 and completed the castle's construction. They retained control of Cloughoughter Castle for centuries, but by 1653, it had been bombed and abandoned. Since then, it has been in ruins, resplendent in a sort of tattered grandeur. It can only be visited by boat but, as a symbol of Ireland's medieval heritage, it is a must-see for history and castle enthusiasts alike.