Aydon Castle is a late 13th century stone fortified manor house, one of the finest of its era. Originally undefended when first built, it was sited with three sides standing against the steep banks of the Cor Burn. Early in the 14th century, an outer bailey curtain wall was added to guard the open side, with a plain arched gateway, a D-shaped and a rectangular flanking tower. The two storey hall block and kitchen wing with an embattled curtain wall make an inner courtyard, with the remnants of a middle courtyard to the west.