St Mary's Church dates to 1870, and is situated at the southern end of Rhoslefain. Its churchyard is rectilinear, and is bounded by the road on its south-east side.

The building is constructed of dressed stone and slate. It consists of a canopied entrance, main assembly room and vestry. Measurements of the main assembly room are given as 29?4? x 15?. Measurements of the vestry are given as 12? x 7?9?. There is a large stained glass window in the south elevation, exposed beams and a pitched ceiling. The church building is now reduntant.

N Vousden, RCAHMW, 9 July 2012