Early Baptist activities in the parish of Llanuwchllyn seem to have taken place in the late 18th century, with the first Baptist service believed to have been held on 19th August 1776. Ainon chapel was built in 1840 for the Primitive Baptist cause on leasehold tenure on the land of Sir Watkin Williams- Wynn, a mile to the south-west of the village of Llanuwchllyn. The first minister, the Rev. Edward Humphries, a local man, was invited to become the minister, in 1847 and he was named in the 1851 Religious Census as the minister of the ‘Primitive Baptist ‘chapel. This Census recorded that the chapel, measuring nine by six yards, contained 68 free seats and 64 others, and that whilst, on 30 March in that year, 12 persons attended the Sunday School in the morning, 34 the afternoon Sunday School, and 20 persons the evening service, the average congregation numbered 45.
A decision was made in 1858 to renovate the chapel, and following the completion of this work, the Rev. J. Jones was installed as the minister: by this time the previous minister, the Rev.Edward Humphries, had emigrated to the United States. The ministry of ‘Jones Llanuwchllyn, as he was known, proved to be extremely fruitful, and ten preachers addressed the very successful Gymanfa [ Assembly ] of Merioneth, Denbighshire and Flintshire held in the chapel in 1859. However, the membership remained at a comparatively low level throughout its existence and there was therefore little need to alter or extend the original chapel: the main improvements made during its history were re-roofing and the installation of gas lighting c. 1939-40.
The chapel was listed as Grade II* in 2001. It is a particularly well-preserved, mid-c.19th century Baptist chapel retaining its largely unaltered exterior and interior character’. It was described in ‘The Buildings of Wales: Gwynedd’ ( 2009 ) as ‘ a charming rural chapel of massive field stones. near -square with deep flat eaves and domestic doors and windows’ with attention also drawn to the simple panelled tall pulpit’.
Ainon had joined the local area pastorate in 1993 but was transferred in August 2017 to the care of Addoldai Cymru.