St Mary's R C Church, Greenhill Road, Lisnavaghrog, Banbridge, County Down, BT32 5QY

St Mary Immaculate Roman Catholic Church, also known as St Mary's, is a double-height Gothic-style church with chancel, built between 1857 and 1858 and dedicated on 17th October 1858. It was designed by William Joseph Barre (c.1826–1867), a Newry and Belfast-based architect best known for designing the Ulster Hall in Belfast, and recorded in The Builder (Vol. 16, 6 November 1858). The church serves the Catholic parish of Annaclone and sits in the townland of Lisnavaghrog, on Greenhill Road north of its junction with Seafin Road, approximately three miles north of Rathfriland.

The building is constructed in random rubble masonry, built to course at plinth level, with granite quoins and dressed stone, and two-stage buttresses. The roof is covered in natural slate with clay ridge tiles and stone skews, and the rainwater goods are cast-iron with ogee moulding. Windows throughout are pointed-arch with irregular long-and-short chamfered granite surrounds, geometrical stone tracery, and leaded glazing.

The principal west gable faces the road and is symmetrically arranged, flanked by diagonal buttresses. A centrally placed pointed-arch doorway features deep-set moulded surrounds with a hood moulding and geometric raised-and-pointed stops; the doors are replacement timber sheeted. Above the door is a large west window with cusped geometrical tracery incorporating quatrefoils and a central cross, with a hood moulding and plain stops. The gable is finished with plain raked stone coping and a bell cote surmounted by an apex cross.

The north elevation is largely symmetrical, though the site drops steeply to the left. It is five windows wide, divided by buttresses, with a ramp running from the centre leftward to serve a secondary entrance at the rear. The south elevation largely mirrors the north, except that the far left bay has a Tudor-arched door matching the rear entrance, alongside a statuette of Our Lady set into a lancet-arched niche.

The rear east gable is blank and surmounted by a filigree apex cross. It is abutted by a chancel of diminished scale, flanked by diagonal buttresses and raised on a tall plinth owing to the sloping site. The chancel has a large east window in a similar style to the west window but with variations in detailing and no hood moulding. To the left cheek of the chancel is a single lancet stained glass window, and to the right cheek is a masonry chimney breaking through the eaves. The chancel is further abutted by a lower flat-roofed single-storey structure over a basement, forming the secondary entrance. This has a Tudor-arched door surround with a raised apex and chamfered jambs with stops, and paired lancet windows over the basement door on the north elevation. On the east elevation, a modern flat-roofed two-storey-over-basement extension abuts the building and is of no architectural interest.

The interior has undergone modernisation that has affected its original character. A high altar was installed during a renovation in 1930. More extensive changes were carried out in 1965, when the original floor, seating, and sacristy were all replaced and the church was subsequently reopened. Following the church's listing in 1977, the interior was further redecorated and rearranged during the tenure of the parish priest installed in 1994.

The church was constructed on a site with a longer history of Catholic worship. Prior to its building, services were held in an adjacent Mass House, visible on the first edition Ordnance Survey map to the south of the present site. That earlier structure was built in 1807 under the Reverend James McKee, and at the same time the current cemetery was laid out. The only surviving physical trace of the Mass House is an inscribed stone now set into the boundary wall at the site. The inscription reads: "AIDED AND GIFTED BY THE DIFFERENT DENIMINATIONS OF CHRISTIANS, THIS CHAPEL BUILT BY THE REVd JAMEs McKEY A.D.1807. AS OFTEN AS DEVINE SERVICE IS PERFORMED PRAYERS TO BE OFFERED FOR ALL PEOPLE WHO CONTRIBUTED TOWARDS THE BUILDING OF." By the 1850s, the growing congregation required a larger building, and construction of the present church began in 1857 under the direction of the parish priest Reverend John Mooney. Griffith's Valuation of 1862 valued the church at £15, a rating maintained through the Annual Revisions until 1929. The original Mass House and a parochial hall to the rear of the church — depicted on the second edition Ordnance Survey map of 1859 — had both been demolished by the time of the third edition map in 1901–02. The flat-roofed single-storey secondary entrance at the rear was built by 1976, when it appears on the current edition of the Ordnance Survey map.

The church sits within a rural setting, with a minor road running adjacent to the west. A graveyard lies to the south, and tarmac car parking to the north and east. The site is enclosed by a rubble masonry wall with modern railings and gates. The inscribed stone from the original 1807 Mass House is incorporated into this boundary wall. The alterations to the gates and railings and the addition of the car park compromise the setting of the church, and the modern rear extension is detrimental, but the building nonetheless remains a good example of the work of a prominent local architect, with its style, proportions, and historic character otherwise well preserved.