Llangelynnin (; Welsh for The church of Celynnin) is a former parish in the Conwy valley, in Conwy county borough, north Wales. Today the name exists only in connection with the church, a school in the nearby village of Henryd, and the nearby mountain ridge, Craig Celynnin.

Llangelynnin Church (Welsh: Eglwys Llangelynnin) is possibly one of the remotest churches in Wales (), and is amongst the oldest; that at Llanrhychwyn, further up the valley, is a little older. The church is dedicated to Saint Celynnin, who lived in the 6th century and probably established the first religious settlement here. It lies at a height of about feet, above the village of Henryd in the Conwy valley, in the shelter of Tal y Fan (), the mountain to the south-west.

Llangelynnin, Conwy

A small and simple building, it probably dates from the 12th century (although some sources cite the 13th century), and was probably pre-dated by an earlier church of timber, or wattle and daub construction. Llangelynnin is also the name of the former parish, the primary school in nearby Henryd (Ysgol Llangelynnin). Celynnin's name is also carried by Craig Celynnin, a mountain ridge adjacent to the church.

Llangelynnin, Conwy

St. Celynnin

Celynnin lived in the 6th century, and according to tradition was one of the sons of Helig ap Glanawg, a prince who lived at Llys Helig (in what is now known to a natural rock formation) before the sea inundated the land off the coast of Penmaenmawr. It is said that Celynnin was related to Rhun, son of Maelgwn Gwynedd, Prince of Gwynedd, who is known to have ruled in the 6th century, and that he was also a brother to Rhychwyn, the saint associated with Llanrhychwyn church.

Llangelynnin, Conwy

Location

Next to the church lie the remains of an Iron Age hut circle, and some stories romantically suggest that this was where St. Celynin himself lived. It is also reputed to have been used as a cockfighting ring. The church is overlooked from the north-east by the adjacent crags of Cerrig-y-ddinas, the site of an Iron Age hillfort. These crags afford wide views down the Conwy valley to the sea, and up the valley as far as Dolgarrog.

Pathways

Many old paths lie in the area, and these routes would have been established at a time when the hills were considerably more wooded.

An old walled bridleway route leads east from the church, down through Parc Mawr, an area of woodland now owned by the Woodland Trust, who are replacing the Forestry Commission's 1960s-planted conifers with native species. The path through the wood leads towards the valley bottom, and to the west a route leads towards Penmaenmawr, past the Bronze Age standing stones of Maen Penddu. To the south-west a path meets the important Neolithic route and Roman Road passing through Bwlch-y-Ddeufaen, which connected the Conwy valley to the north coast near Llanfairfechan, and places further westwards.

The church building

The porch was added in the 15th century, and features an unusual "squint window" in its east (right) wall. Repairs to the porch roof were made using yew wood, and therefore it is quite possible that these came from the churchyard, which at one time contained trees. The door hinges and threshold date from the 14th century, although the door itself is more recent.

The nave is the oldest part of the church, dating from the 12th century, and the present chancel was added later, probably in the 14th century. Originally the nave would not have been paved, as it is today, and indeed, the rear of the north chapel remains unpaved even today. The roof contains dark oak rafters.

The north transept was added in the 15th century and was known as Capel Meibion, the "men's chapel". The window at the back of the chapel was a more recent addition.

Opposite the north transept, a south transept was also added, probably in the 16th century. This was called Capel Eirianws (meaning "Plum Orchard", the name of a local farm), whose owner possibly had it built. This chapel was demolished in the 19th century, but some remains are still visible from outside.

The present east window dates from the 15th century, and replaced a smaller 14th century window.

Since demolition of the south chapel (and the gallery) in the 19th century, the church has changed little.