Farmhouse, Williamstone Farm, North Berwick

Williamstone Farm is a farmhouse built in the mid to later 18th century, featuring two stories and three bays, with later additions and alterations made around 1840. The exterior is harled with painted margins.

On the south elevation, the original three-bay house is centrally located, with two narrow windows spaced widely at the ground level of the outer left bay. The former door at the center has been altered to a window. There is a porch addition to the outer left bay, which has a flat roof, a blocking course, and a cornice, along with a panelled door that includes a small-pane fanlight. To the outer right, there is a single-storey, piend-roofed projecting wing added around 1840, featuring canted windows on the south and east elevations. Additionally, there is a single-storey, piend-roofed bay at the outer left with one window and a dormer on the west elevation.

The north elevation also has three bays, with a flat-roofed porch at the center. There is another doorway in a single-storey bay to the outer right, and a small window in the 1840 extension at the outer left, which is adjacent to a steading range.

The sash and case windows have 12-pane glazing. The house features harled end stacks and raised skews, topped with slate roofs.