Post Office

The Post Office is a three-storey building with a three-window front, constructed from Lanfyllin brick and topped with a steeply-pitched slate roof. It features a large rectangular brick chimney located to the left of the centre. The attic includes one small gabled dormer on the left and a larger one on the right. A dog-tooth brick eaves course adds detail to the roofline.

On the second floor, there are three round-headed casement windows with Y-tracery in their heads. The outer windows on the first floor are similar, while the central window matches their height but has extra light on each side, creating a Venetian window effect. The ground floor has a central window, which was originally a door, featuring a round-arched central light flanked by pointed-arched lights. The basement has camber-headed windows.

To the right, there is a mid-19th century shopfront with steps leading up to a central doorway set back between shop windows. This doorway has panelled jambs, classical-derived pilasters, and a shallow fascia board adorned with quatrefoil decoration above the pilasters, along with raised lettering that reads "Llanfyllin Post Office." Above this area, slate-hanging covers the position of an earlier fascia board that is visible in old photographs.

To the left, there is another mid-to-late 19th century shopfront with steps leading up to an entrance doorway at the corner. A window projecting over the basement window is supported on stanchions, while a larger window faces the Market Square. This section features a dentil cornice. The gable end facing the Market Square has a round-headed casement window near the apex. On the second and first floors, there are two more round-headed casement windows with Y-tracery in their heads, along with an additional similar window to the left of the shopfront.