Located near the village of Crossmolina, this former stronghold was built by the Anglo-Norman Jordan de Exeter family in the 13th century, who established themselves in the region following the Norman invasion of Connacht. The castle’s strategic position allowed the de Exeter family to control the surrounding lands and waterways, playing a significant role in the complex power dynamics between Gaelic Irish clans and Norman settlers.

By the 14th century, the castle had passed into the hands of the Barrett family, one of the prominent Anglo-Norman families who gradually adopted Irish customs and became known as the Barretts of Tirawley. Under their control, Carrowkeel Castle witnessed centuries of conflict, including raids during the Elizabethan wars and the upheavals of the 1641 Rebellion. The Barretts held the castle until the Cromwellian conquest of Ireland in the 1650s, when it was seized and subsequently fell into ruin.

Today, visitors to the site will find only earthworks and scattered stones marking where the castle once commanded the landscape. Archaeological surveys have identified the remains of a rectangular tower house typical of late medieval Irish castles, along with evidence of associated defensive features such as a bawn wall. While the physical structure has largely vanished, the location remains significant for understanding the patterns of settlement, conquest, and cultural exchange that shaped medieval Mayo.