Mostyn House is an early-mid 18th century, three-storey town house, brick-built with a slate-roof and a stucco facade. It consists of 2-units flanking a central-entry, stair-passage and forms an `L' shape plan with a rear unit. Although altered and extended in the early 19th century, it retains many original features including a brick barrel-vaulted cellar, a panelled first-floor room and an attractive well-stair.

It has a fine stucco parapet facade with raised quoins and lugged architraves with keystones. At second-floor there are 3 sash windows, while at first-floor paired sash windows flank a Victorian bay window. At ground-floor, large single window openings (damaged) have segmental arched voussoirs flanking an altered central doorway.

The well stair has a ramped and moulded hand-rail to fluted and turned newel-posts with 3 turned and fluted balusters to each tread. The stair has been altered slightly and part removed at ground mezzanine level, but continues to the second-floor with fielded panelling to the dado. At first-floor the room to right retains its original fireplace surround, with bolection mouldings to the doorways and fielded panelling with a dado rail and a cornice plaster to plaster ceiling.
The building is empty at present, but expected to be converted into flats.
Visited, Geoff Ward, 08/03/2004.