Morwenstow is Cornwall's most northerly parish and its church is set back from high cliffs. The west ends of aisles and the upper sections of the tower, facing seawards are windowless and were probably originally rendered. It stands higher than the Vicarage but lower than the Rectory from which a steep path descends through the large churchyard to the south door.
The church is dedicated to St Morwenna and St John the Baptist. St Morwenna was an early 6th-century saint from Ireland, reputedly one of the many children of the legendary Celtic King Brychan, who settled in Morwenstow while her brother, St Nectan, went to nearby Hartland in Devon. She is said to have asked King Ethelwolf for the land on which to build the church.
St John was added as a dedication after 1285 when the church was given to the hospital of St John the Baptist in Bridgwater by William de Monkton. Bridgwater hospital had already been given Lanteglos church in Cornwall. In 1296 the church was referred to as an 'old and well-known structure'.
It was heavily restored in the 1870s and 1900s but preserves many early features.