The battered remains of this once-strong castle crowns a massive rock with superb views over the pass through the west Wicklow hills. It was built in the 13th century by William Marshall and his son-in-law William de Braose on the site of an Irish fort that Strongbow had obtained. It had a number of owners, notably Roger de Mortimer – who further fortified it – before it fell into the hands of the O’Mores in the 14th century. In 1641 it was taken from the O’Mores by Sir Charles Coote, retaken by Eoghan O’Neill in 1646 and finally captured and dismantled by the Cromwellians in 1650.
William Marshall probably began the enormous rectangular tower on top of the hill. Much of the southern part has now vanished, while the northern portion was remodelled to form a stronghouse in the 16th century and a tower was added to the west wall flanking the entrance. The surrounding walls of the inner bailey were probably built by William de Braose around 1250. These are strongest on the vulnerable east side where there is a gateway flanked by oblong towers containing guard rooms.