20 Castle Street, Newry, Co Down, BT34 2BY

20 Castle Street is the central building of a terrace of three three-storey early Georgian classical townhouses, with basement and attic storeys, built between 1760 and 1779. It retains most of its original features and is well proportioned and elegant.

The street façade is three bays wide, constructed of random granite rubble with a moulded granite eaves course. The gabled natural slate roof features a copped verge, brick chimney at the left, cast iron skylight to the front pitch, and concealed gutters with a metal downpipe at the left.

At ground floor centre is a grained tongue-and-groove door with a plain transom over, its exposed timber frame resting on painted granite blocks with cement-rendered reveal and head. To the right is a pair of tongue-and-groove doors with the right one fitted with a wicket door, both with louvred transoms, set within a segmental-headed coach arch trimmed with ashlar granite. The arch head is infilled with recessed rubble stone with strap pointing. To the left of the front door is a 2/2 sliding sash window with a rendered lintel extending the full width of the bay. A painted timber lintel at ground level indicates an infilled basement window below. Three 1/1 sliding sash windows occupy each upper floor, aligned with the ground floor openings. All windows have exposed boxes, rendered reveals, and painted granite cills; those at the top are diminished in height with unequal pane sizes, suggesting they were originally 6/3 sashes. Between the front door and coach arch is modern metal railing over a chamfered granite plinth. Left and right gables form party walls with adjacent properties.

The rear elevation follows the same composition as the front. A three-storey gabled return projects from the right bay. At its first floor is an exposed box 6/6 sliding sash window, and at second floor a similar 6/3 window (ownership of this top window is uncertain as it may belong to no. 20). Neither has a cill and the top window is diminished in height. The return has a gabled natural slate roof with a rendered chimney rising from the left wall head and half-round metal rainwater goods. The right cheek wall is random rubble (painted at ground floor) and blank, while the left cheek at first floor displays three 6/6 sliding sashes, and at second floor three diminished height 6/3 sashes, all aligned vertically. All windows to this elevation have shallow segmental brick heads but no cills. The rear gable is wet-dashed random rubble with a small casement window at the right. A second return abuts this gable, with a gabled natural slate roof, half-round metal rainwater goods, and wet-dashed walls. The right wall is in line with the left wall of the first return and is random rubble. Windows comprise 1/1 sliding sashes at first and second floors, with the top one diminished in height; both have segmental brick heads but no cills. A further outbuilding of no architectural interest adjoins the second return.

The building appears on John Rocque's 1760 town map of Newry and is definitely recorded on the 1838 valuation map when valued as a house at £15. It appears on the 1861 Ordnance Survey map with its returns intact, and was described as three and one-third storeys high in the 1863 valuation. The terrace composition suggests that this building and no. 22 were erected as a single unit.