Nenagh Castle is Nenagh’s oldest building, and its construction in the 13th century laid the foundation for the development of the town. Theobald FitzWalter, whose successors would become Earls and Dukes of Ormond, built the castle, and upon its completion c.1220 it served as the main seat of the Butler family until 1391.
The castle boasts the finest cylindrical keep in Ireland. Like most keeps, it formed part of the perimeter of the fortress, being incorporated in the curtain walls surrounding a five-sided courtyard. The keep features four storeys. Thanks to a recent renovation, this wonderful landmark now represents the town’s premier tourist attraction.