The much-photographed Castle Island within Lough Key Forest Park, near Boyle, Co. Roscommon.
There is reference to Castle Island as early as 1184. During this time the park was called Moylurg and the local chieftains were the McDermotts. Their official residence was on The Rock, now called Castle Island.
The McDermotts ruled the area until the 17th century when it was granted to the King family from England under the Cromwellian settlement. The King family spent their time between the town of Boyle and Moylurg, which they renamed Rockingham. The castle was rebuilt as a folly during the King family's reign.