Nevern 1 is an incomplete roman-letter and ogam-inscribed slab of spotted dolerite. It is currently built into the sill of the east window of the Henllys (south) chapel of St Brynach's Church, Nevern (NPRN 300317). It was first noted in 1904, adjacent to Nevern 3: in use as a door lintel in the narrow passage that opens off the west wall of the Henllys Chapel. It was removed in 1909 and placed in its current position.

Dimensions are given as 159cm height x 33cm > 16.5cm width x 10cm diameter. The top and right side of the stone are missing as a result of trimming for reuse as a lintel, meaning the ogam inscription is incomplete. The carving is thought to date to the second half of the 5th or earlier 6th century. The roman-letter inscription has been translated as `Maglocu son of Clutorius?. The incomplete ogam inscription has been translated as `of Maglicu son of Clutar ??.

Sources include:
Edwards, N. 2007, Corpus of Early Medieval Inscribed Stones and Stone Sculpture in Wales

N Vousden, 15 October 2018