House, including forecourt railings and gate

23-25 Castle Street is a pair of late-Georgian town houses, each two storeys high and featuring three bays. The houses have pebble-dashed walls painted cream, a slate roof, and roughcast stacks at the ends and in the center. Both houses have a central entrance; No 25 features a fielded-panel door, while No 23 has replacement double-panel doors. Each entrance is topped with a 5-pane overlight and has a restored segmental canopy supported by moulded wooden brackets, with details in No 25 reinstated to match No 23. The windows are renewed 16-pane hornless sashes with cambered heads.

In front of each house, there is a dwarf coped stone wall and restored wrought iron railings that include twisted spear and cast-iron urn finials. Each house also has a gate added in a similar style.

The interior of the house is centrally planned with an entrance hall, leading to an open-well stair at the rear, which features plain balusters and a turned newel.