2, 4 Northumberland Street, Edinburgh

2 and 4 Northumberland Street in Edinburgh is a four-storey and basement terraced block designed by Robert Reid and William Sibbald in 1812. The building features a six-bay façade with a band course at the principal and first floors, a cill course at the first floor, projecting cills at the second floor, and a continual cornice at the second floor that is returned and terminated at the corners. There is also a cornice and blocking course at the third floor, with ashlar steps and entrance platts that oversail the basement.

The principal elevation includes a nine-panel timber common stair door in the third bay from the right, and another nine-panel timber door in the third bay from the left, both with plate glass rectangular fanlights. The remaining bays at the principal floor have windows, and there is regular fenestration on the floors above and in the basement. The basement features a four-panel, two-leaf timber door in the penultimate bay to the left, and a two-leaf timber door in the penultimate bay from the right, both with shallow multi-pane rectangular fanlights, and a flagged basement area.

The northeast elevation is a four-storey and basement, six-bay elevation that transitions into 2-4 Northumberland Street. It has regular fenestration across all floors, with blind windows in three bays from the right at the principal, first, and second floors, and blind windows in the penultimate bay from the left and at the outer left on the third floor. This elevation also features a flagged basement area.

The southeast elevation adjoins another terrace, which is listed separately as 10-14 Nelson Street. The building predominantly has twelve-pane timber sash and case windows and an iron balcony spanning the bays at the third floor. The roof is a grey slate M-roof, with a rendered shouldered wallhead stack centered on the east elevation and a random rubble shouldered wallhead stack with broached ashlar quoins centered on the north elevation, both coped and featuring circular cans.

The interiors have not been seen since 1997. The property also includes ashlar copes topped with iron railings that have spear-headed balusters and urn finials, along with cast-iron lamps mounted on the railings with glass globes.