Mounie Castle is a good example of a Laird's house.  It was small fortalice of the Setons originally constructed in the mid 16th century, it was restored in 1898. Mounie was a property of the Setons, but was sold to the Farquhars in 1634. Thereafter, it was passed on to the Hays of Arnbath in 1701. It was later recovered by a branch of the Setons of Pitmedden, who later sold it in 1970.

The Setons of Mounie originated through the foreseeing alienation of Church lands on the eve of the Reformation. In 1556, the Chancellor of Aberdeen, Alexander Seton, had several of the holdings now comprised in the estate of Mounie in possession, and his brother William, the laird of Meldrum, got the rest. Upon resignation, in 1575, the whole were granted by the Bishop to William's second son, John Seton of Lumphart and Broomhill, thereafter John Seton of Mounie. His line is extinct, and the estate is now possessed by a descendant of his half brother, James, the first Seton of Pitmedden, whose family are the only Setons now in Aberdeenshire.

The building conforms to the T-plan with a long main block of three storeys running N to S, and a circular stair tower projecting westwards midway along the W front. Unfortunately the original crenellated parapet is now gone and the roofline now meets the walling.  The walling itself, no longer exposed stonework is now harled and plain and roughcast and the gables crowstepped. The modern wing, attached to the SW, is actually a separate building extending from the NE.  A rectangular dovecot dated 1694 at Mounie was restored by Sir Robert Lorimer as a garden house in 1898, although no dovecot features survive.  The castle is private.