Quintin Castle, 3 Kearney Road, Ballymarter, Portaferry, Co Down, BT22 1QE

Quintin Castle is a large, castellated mansion of around 1855, built on the rocky shoreline of the south-east coast of the Ards peninsula, approximately three miles south-east of Portaferry. It overlooks Quintin Bay and stands on the site of a smaller twelfth-century castle or tower house, which was itself extended in the mid-seventeenth century.

The building is generally rectangular in plan, oriented with its short sides to north and south. It is predominantly two storeys, with a large three-storey tower rising from near the south-east corner. The structure incorporates an outer bailey—a crenellated wall of varying height, finished in flat rubble with corner towers and pointed arch gateways, enclosing forecourts, lawns, and a folly tower to the south.

The west-facing front elevation divides into three distinct sections. The largest southern section is two storeys and symmetrical, with the main entrance housed within a centrally placed three-storey projecting tower. The entrance consists of a pointed arch opening in dressed sandstone, containing timber-sheeted double doors. A tall four-storey tower rises immediately behind this section to the east. To the north, this section adjoins a slightly lower two-storey block that projects further westward, which in turn connects to a three-storey tower marking the northern end of the elevation. The entire front is finished in rubble with dressed sandstone dressings to the openings. Windows are generally flat-headed with two lights and stone mullions, in timber frames (probably a mixture of casement and fixed lights). Ground-floor windows are taller. The entrance tower features single pointed arch windows to the first and second floors, with pointed arch openings on the ground floor to north and south. The lower two-storey section has a large, recently inserted opening on the ground floor containing a modern window with timber-sheeted door. The northern tower has a narrower ground-floor doorway similar to the main entrance. Tall battlemented walls project from the north and south edges of the elevation, enclosing the front courtyard.

The north elevation is partly obscured but consists of a two-storey section to the left and the three-storey tower to the right. The left section is recessed and stone-faced, while the centre and right portions (including the tower) are cement-rendered, with a single first-floor window and a small window with plain sheeted door to the ground floor.

The south elevation comprises the south façade of the main two-storey section. A narrow three-storey tower projects from the centre, similar to the front entrance tower but rendered. The façade to the right of this tower is also rendered, while the left portion remains stone-faced. Both sides have windows to each floor; those on the left are three-light (instead of two), while the ground floor right window is now a single pane.

The rear elevation is entirely rendered. It shows the two-storey sections with the large three-storey tower projecting from the left side. A modern single-storey lean-to conservatory stands to the immediate right of the tower, with a large single-storey lean-to (possibly an earlier conservatory) having been removed from the far right. Windows on both storeys of the two-storey sections are generally three-light with bevelled reveals and taller ground-floor windows. The far right has a modern glazed door, and the third window from the right has had its mullions removed. On the east face of the tower's ground floor is a large pointed arch window containing three pointed arch lights with three quatrefoils above. At high first-floor level on this face is a three-light window, with a two-light window to the right on the south face. At second-floor level on the south face is a much smaller three-light window with timber mullions.

The taller two-storey section and all towers feature oversailing stepped battlements resting on dentilled corbelling. The lower two-storey section has plainer, flush battlements. A large rendered chimney stack rises from the battlements on the north side of the taller section.

The bailey walls, constructed in flat rubble of varying height, are tall (up to approximately three metres) on the west, south, and north sides, and low (approximately one metre) on the east, providing clear views to the sea. All are finished with crenellations and interspersed with small two- and three-storey corner towers and pointed arch gateways. The western walls enclose a tarmac forecourt; the eastern enclose a lawn adjacent to the house; and the southern enclose an additional long rectangular lawn leading to a folly tower.