Balfour Mains Farmhouse incorporating Balfour Castle, Balfour Mains, Kingoldrum

Balfour Mains Farmhouse, built around 1840, features late 19th century additions at the rear and incorporates a section of an early 16th century castle at the south corner. The farmhouse is three stories tall, with the upper floor extending above the eaves, and has a symmetrical three-bay principal elevation facing southwest. It includes a two-storey wing at the rear, creating an L-shaped plan, along with single-storey additions at the re-entrant angle. The structure is made of tooled red sandstone rubble with roughly squared quoins and has ashlar window margins. Gablet dormers topped with finials are present, and there is a single-storey porch with a piended roof added around 1999 at the center of the southwest elevation.

The windows mainly feature 12-pane glazing set in timber sash and case frames. The farmhouse has a pitched roof covered with grey slates, and chimney stacks are located at the gables, with the south gable stack heightened in brick and the north gable stack replaced in brick. The rear addition has coped sandstone ridge chimney stacks.

The interior, partially observed in 2013, includes rooms arranged around a central dog-leg staircase with a decorative cast iron balustrade. Some rooms have window shutters and panelled timber doors.

The fragment of Balfour Castle is an approximately 17-meter tall, tapering round tower topped with a later monopitch slate roof. It is constructed of rubble with dressed stone around various openings, including arrow slits, and features stepped string courses above these openings. At the base, there are oval gunloops and a later entrance leading to a vaulted basement. A fragment of a return wall is visible on the northeast side.