This four-storey tower house, also known by its Irish name Carraig a’Chabhlaigh meaning ‘Rock of the Fleet’, rises from bedrock at the mouth of a small river flowing into this sheltered inlet on Clew Bay’s northeastern edge. Built as a stronghold of the Burke clan, descendants of the Anglo-Norman de Burgos, the castle’s plain exterior conceals a carefully designed interior complete with spiral staircases tucked into the walls, a garderobe that cleverly empties into the sea below, and a principal chamber on the top floor with its own fireplace and hoisting door for supplies.

The castle’s most famous resident was Gráinne Ní Máille, better known as Grace O’Malley or Granuaile, the legendary pirate queen who made this her base after marrying Richard an Iarainn Burke in 1564. From Rockfleet’s protected harbour, she commanded her fleet of galleys, maintaining her family’s seafaring traditions of fishing, trading, and the occasional raid on passing merchant vessels. Her activities drew the ire of Galway’s merchants, who dispatched a fleet under Captain William Martin to besiege the castle in 1579; Gráinne’s forces not only repelled the attack but nearly captured Martin himself. Though political turmoil under English governor Sir Richard Bingham saw her fleet destroyed and properties confiscated by 1591, Gráinne’s famous audience with Queen Elizabeth I in London secured her return to Rockfleet, where she’s believed to have died in 1603.

Today, this National Monument stands as a tangible link to Ireland’s turbulent medieval past, its restored gabled roof and corner bartizans courtesy of 20th-century conservation work. The Office of Public Works continues restoration efforts on the structure, which once formed part of a larger complex including a bawn wall and associated settlement. Visitors can explore the narrow chambers connected by the southeastern spiral staircase, peer through the small defensive window loops, and imagine supplies being hauled through the large pointed arch on the upper floor, all whilst the same tides that once carried Granuaile’s galleys continue their eternal rhythm against the castle walls.