15th century chapel dedicated to St Mahew; in 17th century nave became parish school; chancel retained as family burial vault of Napiers of Kilmahew; restored Ian Lindsay and Partners, 1953-55 as Roman Catholic parish church. Rectangular-plan church aligned E to W, with lean-to vestry against N wall. Painted harl with red sandstone crowstepped gables; masonry carved mouldings, roll-moulded at E end, chamfered now painted. Red sandstone ashlar birdcage bellcote.
S ELEVATION: 4-bay nave with higher chancel at E end, crowstepped gables. Door to outer left, 3 window symmetrically disposed to right. 2-bay nave to outer right; boarded door to left, window to right, roll- moulded surrounds.
N ELEVATION: nave with window off-centre to right, lean-to outshot at W end; chancel at E end, roll-moulded window to right.
E ELEVATION: gable, wall thickness deeper, small roll-moulded window at ground to right; small window in gablehead.
W ELEVATION: red sandstone apex birdcage bellcote, reconstructed 1950s on 18th century design, ashlar bell-cast roof, ball and cross finial. Window at ground to outer left.
12-pane sash and case timber windows; multi-paned window at E end. Grey slate roof, red sandstone roof ridging.
INTERIOR: Early Christian cross-inscribed stone slab at entrance. 1950s interior, glazed screen dividing main body of nave from entrance; carved and painted statue of Saint Margaret, painted flowing banner. Sculpted crucifixion scene above chancel against painted backdrop latin inscription beneath with datestones 1467 and 1955. Chancel area, red sandstone chancel arch; rubble; round-arched sedilia. Aumbry now glazed. Stained glass window in gable.
GRAVEYARD: number of plain grave slabs probably dating from the 17th century.
BOUNDARY WALL: rubble boundary wall with boulder coping.