Carefully reconstructed and standing just under two metres in its current position, it is a piece of late fifteenth or sixteenth-century ecclesiastical stonework removed from its original home and reassembled here with some precision. The doorway is pointed, narrows slightly towards its base, and is worked with roll and hollow mouldings in the chamfer, the angled cut along the edge of the stonework. A pointed hood-moulding runs over the opening and terminates in fluted chamfer-stops, decorative end-pieces where the moulding meets the wall, with the northern stop the better preserved of the two. The inner faces of the jambs carry pock-dressing, a deliberately roughened surface texture. Fragments of tracery, the ornamental stonework associated with window or arch openings, flank the doorway on either side, and a sandstone jamb with a slight curve and chamfered edge sits above it. The bulk of the structure is sandstone, with one small section of jamb in limestone.

According to Lewis's Topographical Dictionary, this doorway was taken from the Woman's Church at Mona Incha, a monastic island site in a bog near Roscrea that was associated with an early Christian community and later with Augustinian canons. Mona Incha has a long and layered history, and the Woman's Church, a secondary structure on the site, appears to have been dismantled at some point with its stonework dispersed. The doorway was brought to Birchgrove and reassembled, apparently with care, as the proportions and jointing suggest a deliberate attempt to preserve the piece rather than simply repurpose the stone. Other loose architectural fragments connected to the same source have since been moved to Damer House in Roscrea, a Georgian building now used as a heritage centre, where they are held separately from this doorway.