Bangor Museum & Art Gallery, including outbuilding at NW end

Bangor Museum & Art Gallery, which includes an outbuilding at the northwest end, is a two-storey building with a basement and attic. It is constructed of snecked rubble with freestone dressings, featuring quoins, a first-floor cill band, a plinth band, and architraves. The roofs are covered with green slate and have cresting, rubble chimney stacks, and overhanging eaves. The building has one, two, and three-light mullioned windows, mostly with sash glazing. The ground floor windows have transoms below cusped quatrefoil panelled heads with patterned glass. The front has a two plus one window arrangement, with a projecting gabled bay on the left and a hipped roof at the right end. There is a pointed entrance and a two-light plate-traceried window in the hall to the right. A pitched roof dormer with bargeboards and fishscale slates is located at the gable.

To the right, there is a Caernarfon arch doorway set in an attached rubble wall. The property is enclosed by contemporary cast iron railings and accessed through chamfered gate piers topped with pyramidal caps and billet moulding.

The left side elevation features a two plus two window arrangement, with the advanced left part consisting of twin asymmetrical gable ends, the right one being slightly smaller, and a pointed relieving arch. There is a similar dormer window on the right. The northwest elevation has a three-window arrangement with a central gable and a similar dormer on the left. A rear entrance at basement level is located below a two-light plate traceried window, similar to the front. The window arrangement on this side is asymmetrical, with a panelled quatrefoil head to the right only. The main window on the northeast side is sexfoil headed and lights the staircase, which features a Gothic stack.