Built around 1626 by the influential Browne family, who had arrived from England to establish themselves as major landowners in Connacht, this fortified house represented their aspirations to control the lucrative trade routes along Ireland’s western coast. The castle’s strategic position allowed the Brownes to oversee maritime commerce whilst maintaining a defensive stronghold during a particularly turbulent period in Irish history.

The castle’s relatively brief occupation speaks to the volatility of 17th-century Ireland. During the Confederate Wars of the 1640s, the Brownes found themselves caught between competing loyalties; as Catholic landowners with English origins, they faced suspicion from both sides of the conflict. The family eventually abandoned Portroyal, relocating to the more secure Westport House, which would become their permanent seat. The castle saw military action during the Williamite War of 1689-91, when it was briefly garrisoned, but by the early 18th century it had fallen into disrepair.

Today, visitors can explore the substantial remains of this four-storey tower house, which retains much of its original defensive architecture including gun loops, a murder hole above the entrance, and the remnants of a bawn wall. The structure showcases the transitional style of early 17th-century Irish architecture; combining medieval defensive features with more comfortable domestic arrangements that reflected the Brownes’ desire to create a prestigious family residence. Its location offers spectacular views across Clew Bay and its numerous islands, providing insight into why this spot was chosen for such an important fortification.