Castlenavin, 1 New Line Road, Castlenavan, near Loughinisland, Downpatrick, Co Down, BT30 8PN

Castlenavin is a relatively large, plain single storey gabled house of probable pre-1834 construction, located on a slight rise to the north of New Line Road, less than a mile west of the village of Loughinisland and approximately 5 miles west of Downpatrick.

The house is built to a symmetrical plan with its front façade facing south. At the centre of the front is a flat roofed porch of early 20th century date, fitted with a modern glazed doorscreen to the front and narrow windows to the east and west faces. To either side of the porch are three windows with modern PVC frames, now unevenly spaced following the recent removal of two canted bays that formerly projected from the front. The west gable contains a small semicircular-headed upper level window with sash frame (2/2 horizontal glazing bars), with a similar window to the east gable. At ground floor level on the east gable is another window with plain sash frame, to the right of which the gable is abutted by a high rubble wall extending from an adjacent outbuilding. The rear façade includes a partly glazed door reached via a short flight of steps, flanked by windows; the window to the left of the doorway may have been enlarged in recent times. All rear windows have PVC frames.

The front façade and gables are finished in painted lined render with in and out quoins and a dentilled eaves course to the front. The rear is finished in plain unpainted render. The gabled roof is slated with three cast iron skylights to the rear and four symmetrically arranged rendered chimney stacks. Cast iron rainwater goods are present throughout.

Extensive outbuildings stand to the rear. To the north of these outbuildings is a derelict single storey vernacular dwelling, itself recently used as an outbuilding, featuring a slated roof, rubble façade and remains of a large kitchen fireplace.

The dimensions of the present house match those of the building shown on the 1834 Ordnance Survey map and noted in the 1836 valuation for this site, suggesting it is of pre-1834 construction and possibly dating from the later 1700s. In 1836, the resident was William Blackwood; the Blackwoods remained present circa 1860. The canted bays and flat roofed porch were added in the later 19th century or circa 1900. The bays were removed sometime after 1978. Window frames are now largely PVC. The building is not of special architectural or historic interest.