21, Cannon Street

21 Cannon Street is a town house built around 1860. It features an ashlar facade and side walls, with a rubble rear wall and a hipped slate roof that has a chimney on the left side. The building has a double pile, three-bay plan and is two storeys tall, designed in a classical style. Notable architectural details include rusticated quoins, channelled rustication on the ground floor, a string course, and a moulded eaves cornice supported by consoles.

The facade is symmetrical, with a central panelled door that has a fanlight, set within a recessed architrave. This door is framed by a rusticated surround topped with a keystone and a small cornice that projects forward from the string course. There are two ground floor windows with rusticated surrounds and three first floor windows with eared architraves, all of which are sashed with glazing bars. The right return wall features similar windows. The rear wall includes a service wing attached to the first bay and a round-headed stairlight with glazing bars.