Auchans House was originally a mid 16th century stone Z-plan tower house, founded by William Wallace of Dundonald and Auchans. Built with materials removed from Dundonald Castle, the long main block, is of three storeys and an attic. With its vaulted basements and being of slightly different construction, it could be part of an earlier building. Flanking its south wall, is a central round stair tower and a terrace which was originally encased by a barmkin wall. In 1640, the house was converted into a L-plan, when Sir William Cochrane of Cowdon, added a wing of three storeys and a garret. In 1667, the wing was extended by the addition of a block with a crow-stepped gable, flanked by a round stair tower and a corbelled-out square, round angle tower. The main entrance in the re-entrant angle, was through a Renaissance-style doorway below an armorial shield in the square stair-turret. Sadly this once magnificent Scottish baronial residence, is now a complete ruin.