Mount Street House including forecourt wall and railings

Mount Street House is a 19th-century building that is raised above street level and situated behind a narrow forecourt. The street-facing side is stuccoed and consists of three storeys with three windows. It has a slate roof featuring flanking stacks and projecting eaves, along with bands at the second and first floor levels and plain pilaster strips.

On the second floor, there are three 9-pane windows. The first floor has two-light casements with margin lights in the middle and left-hand bays, while the right-hand bay features a sash window with marginal glazing bars. The ground floor is accessed by a flight of four steps leading up to a wide doorway in the centre bay, which is pedimented and flanked by fluted pilasters, side lights, a rectangular fanlight, and a six-panelled door. To the left, there is a three-light canted bay with sash windows that have marginal glazing bars on the front, and to the right, a single sash window also with marginal glazing bars.

The forecourt is enclosed by a stone wall with coping, and features 19th-century railings with alternately straight and wavy uprights, the straight ones topped with arrowhead finials. Standards are placed at intervals and topped with urn finials. At the rear, there is a crosswing with a gable end that has two storeys, a basement, and an attic. The attic level includes a casement window, while the other floors have a 16-pane sash window and a twelve-pane sash window located at the first floor at the angle between the main block and the crosswing.

The interior is said to retain early 19th-century details.