Dungarvan Castle, Anglo-Norman castle at Dungarvan Harbor, Ireland.

Dungarvan Castle is an Anglo-Norman fortress founded in 1185 at the mouth of the Colligan River. Its earliest part is a 12th-century polygonal shell keep, a form common in England but rare in Ireland, enclosed by a curtain wall with corner and gate towers. A two-storey military barracks from the early 18th century stands within the walls and now holds an exhibition on the castle's history.

Dungarvan Castle was founded in 1185 by Prince John at the mouth of the Colligan River, one of several castles raised in south-east Ireland around that time. The 12th-century polygonal shell keep is the oldest surviving part. A two-storey military barracks was built inside the walls in the early 18th century. Used as a barracks during the Irish Civil War, the castle was set on fire by the IRA in August 1922, later restored as a Garda Síochána station until 1987, and is now a National Monument.

The castle's Irish name is Caisleán Dhún Garbhán, and the barracks inside the walls now hold an exhibition on the castle's history plus an audio-visual show. Guided tours run from the restored early 18th-century two-storey barracks, the building visitors enter first.

The grounds are open seasonally with self-guided and led tours available to explore the castle and nearby areas. It helps to arrive early in the day to see all sections without feeling rushed.

The polygonal shape of the central tower is uncommon in Irish castles and reflects English military design from that era. This geometric style provided better defense from multiple angles at once.