This castle dates from the early days of the Anglo-Norman settlement in Ireland. It was built c.1209 to safeguard the entrance to Dungarvan Harbour. The polygonal shell keep – a rare building type in Ireland – is the earliest structure on the site. The castle has an enclosing curtain wall, a corner tower and a gate tower. Within the wall is a two-storey military barracks, which dates from the first half of the eighteenth century. It was used by the British Army and the Royal Irish Constabulary until 1922. During the Irish Civil War Dungarvan Castle was destroyed by the Anti-Treaty IRA.  It was subsequently refurbished and served as the Headquarters of the local Garda Síochana.