Parochial House, St Peter's Cathedral, St Peters Square, Belfast, Co Antrim, BT12 4BU

The Parochial House at St Peter's Cathedral is a four and a half storey L-shaped building constructed of ashlar sandstone, begun in 1867 to designs of John O'Neill. It is attached to the south east corner of the symmetrical Gothic Revival cathedral of 1866, which was built in Scrabo sandstone by Jeremiah McAuley.

The south elevation, which fronts onto modern housing on Milford Place, features the main entrance. The east elevation of both cathedral and house overlook St Peter's Square East and St Peter's Place, with a pedestrian entrance to the grounds accessible from St Peter's Place. The grounds of both buildings are enclosed by stone walls and piers with ornamental metal railings, surrounded by hard landscaping with paviors. A modern building, St Peter's Immaculata Youth Centre, stands on the north side of the grounds.

All windows are replacement timber double-glazed units with smooth sandstone heads, chamfered sandstone reveals, and stone cills. The roof is of natural slate with gabled form and copings to the gables.

The south elevation is positioned at the extreme right side of the cathedral's south elevation. A four and a half storey gable rises to the right, with two windows to each floor, equally spaced and aligned vertically. A continuous sandstone cill sits beneath the second floor windows. The gable is corbelled at the eaves and terminates at the apex with a stone Celtic cross. To the left of this gable is a two storey modern extension built in natural stone with a flat roof, metal railings to the parapet, and timber fencing behind. An entrance at ground floor level, positioned to the left of this extension, has a modern front door set beneath a pitched slate roof over a projecting porch with timber brackets on either side. Two windows appear above on the first floor, with a third floor level visible above the extension, featuring two windows beneath stone modillions under the eaves.

The west elevation abuts the south elevation of the cathedral. It comprises a four storey gable to the left, a two storey modern extension to the right, and an exposed third storey of the original building behind. The gable features steps leading to first floor timber double doors at the extreme left and two narrow lancet windows with trefoil heads to the right. At lower ground floor level is a barred window set between reveals. An arched opening beneath the steps leads to a basement area. A continuous stone cill course runs beneath the two second floor windows and similar windows above on the third floor. The gable has a plain apex. The modern extension to the right has two windows at ground and first floor levels, with metal railings to the flat roof parapet above and one window to the exposed third floor of the original building. This modern entrance extension contains stained glass by CWS.

The east elevation comprises the main block to the left and several smaller elements to the right linking with the cathedral's south elevation. The main block is four storeys with an attic, featuring three windows on each level, fairly evenly spaced, with ground floor windows being smaller than those above. A continuous stone cill course runs beneath two second floor windows. Stone verges flank the natural slate roof, and a single rooflight is roughly aligned with the middle windows. Stone modillions appear beneath corbelled eaves. A tall stone wall with a door to the rear yard sits on the right side, with several small modern flat-roofed extensions added to the north elevation to provide additional service space.

The north elevation abuts the side chapel on the cathedral's south side but rises above it with an exposed gable wall at high level and modern flat-roofed extensions extending from the rear yard. The exposed gable wall contains windows on the second and third floor levels, approximately centred. At half-landing level on the extreme right is another window, and at attic level on the extreme left is a small square single-paned window close to the verge. The ground, first and second floor levels of the gable are obscured by the modern extensions.

The cathedral and parochial house are located in the Divis area of central west Belfast. The twin spires of St Peter's Cathedral form a prominent feature of the Belfast skyline, visible from a considerable distance, though the immediate setting is densely built with housing and other buildings.

The external walls are constructed of sandstone, the roof of natural slate, windows are replacement timber double-glazed, and rainwater goods are of cast iron or cast metal to the south elevation.