Seion's Methodist congregation, or 'cause' was established in 1792 and the original Vernacular style chapel, built in 1817, still remains as a good example of an early nineteenth century long-wall chapel. The entrance faces towards the road on the north-western side and a Sunday School lies nearer to the road on the south-western side. The Sunday School was added in 1927 when the chapel was repaired for a total cost of £1,000. It was still being used as a chapel in 2007.

A number of famous preachers are associated with this chapel. Dr. John Williams (Bardic name Brynsiencyn) preached for the last time on 4 Sept 1921, a month before his death and John Elias first preached in the present pulpit.

RCAHMW, June 2009.