Castle Fraser is the most elaborate Z-plan castle in Scotland and one of the grandest 'Castles of Mar'. It is located near Kemnay in the Aberdeenshire region of Scotland. The castle stands in over 300 acres (1.2 km2) of landscaped grounds, woodland and farmland which includes a walled kitchen garden of the 19th century. There is archaeological evidence of an older square tower dating from around 1400 or 1500 within the current construction.
Originally known as Muchall-in-Mar, construction of the elaborate, five-storey Z-plan castle was begun in 1575 by the 6th Laird of Fraser, Michael Fraser, on the basis of an earlier tower, and was completed in 1636. A panel on the northern side of the castle is signed "I Bel", believed to be the mark of the master mason John Bell of Midmar, the castle is a joint creation over several decades with another master mason of this period, Thomas Leiper.
Castle Fraser is contemporary with other nearby castles: Craigievar Castle, Crathes Castle and Midmar Castle which are also believed to have been designed by the Bell family of master masons.
The castle was modernised in a classical style in the late 18th century, with a new entrance inserted in the south side and sash windows throughout. This work was supervised by Elyza Fraser, the lady laird, assisted by Mary Bristow. Elyza was also responsible for the landscaping of the grounds, sweeping away the remains of the original formal gardens and orchards, and for the construction of the impressive octagonal stable block.
The interiors of the building were entirely reconstructed again between 1820 and 1850, by Charles Fraser, using the architects John Smith and William Burn. The Library is a fine example of John Smith's regency style with Tudor detailing. Many of William Burn's more extravagant gothic designs for the most important rooms were not carried out, although a gothic style pipe organ was installed (now removed to Kemnay Church).
External works during this period included the construction of the twin gatehouses (still extant), and a grand domed stair and access corridors with loggias in the courtyard (removed).