On a rock in the middle of the River Suir, this remarkably complete medieval fortress can trace its history from the 3rd century, when a fort was first built on the rock—hence the town's Gaelic name, “City of the Fishing Fort.” The present structure, which belonged to the Butler family for 600 years (1375–1961), is Norman. It has a massive keep, high walls, spacious courtyards, original gateways with a portcullis still intact, and a fully restored great hall. The interpretive center offers an engaging 20-minute video introduction to the region’s major historic sites, and you can take a guided tour of the castle grounds.