Llanwnda 4 was found during the restoration of St Gwyndaf's Church (NPRN 308468) in 1881. The restoration included the rebuilding of the nave, and the stone was incorporated into the fabric. It is built high up into the external south wall of the chancel, towards the west end. The stone is one of eight early medieval cross-carved stones associated with the church (see NPRNs 422430-422432, 422434, 422435,421734, 92655) suggesting it was an early ecclesiastical site of some significance.

The stone fragment, possibly local dolerite, has been broken up for use as building material. Measurements are given as 46cm height (approx.) x 46cm width (approx.). Only one face is visible. It is incised with a fragmentary, roughly equal-arm, linear cross, enclosed within a linear ring. The carving is thought to date to the 7th to 9th century.

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

N Vousden, 12 January 2018