The castle was protected by a steep drop to the beach, and a ditch on the landward side, with a drawbridge. Built by the MacDougalls in the 13th century, the castle passed to the MacDonald Lords of the Isles at the beginning of the 14th century before being acquired by the MacLeans of Duart in 1493.
In 1674 the Campbell Earl of Argyll occupied Aros (and Duart) with 2,000 men to punish the MacLeans of Duart, resulting in much bloodshed.
The lands later passed to the Campbells, but in the 18th century Aros lost importance in favour of Tobermory, with its more sheltered harbour.
It is possible to walk around the ruins of the castle at your own risk.