On the banks of Lough Ree, the remains of Rindoon Castle, County Roscommon built by Geoffrey de Marisco, Justiciar (or head of government) in Ireland from 1227-35. Located on a peninsula jutting out into the lake, the castle commanded views both north and south, and was a key feature of an Anglo-Norman settlement established immediately outside its walls.

Within decades of being completed, Rindoon Castle had been attacked by the native Irish who seized control of the entire site before the middle of the 14th century. Around this time the adjacent town was also abandoned, although sections of its walls remain standing. Some 200 years later the castle was rebuilt as part of the Elizabethan conquest of Ireland but later once more abandoned and it has remained a ruin ever since.