Saint Nectan's Glen is an area of woodland in Trethevy near Tintagel, North Cornwall stretching for around one mile along both banks of the Trevillet River. The glen's most prominent feature is Saint Nectan's Kieve, a spectacular sixty foot waterfall.

There is an early twentieth century half timbered private residence known as The Hermitage. A medieval chapel close to The Hermitage is open to the public.

Further downstream are the brick remains of a pottery which was destroyed in a fire in the mid twentieth century.

Saint Nectan's Kieve in Saint Nectan's Glen is a plunge pool or basin fed by a sixty feet high waterfall on the Trevillet River in Trethevy, North Cornwall. Kieve is the Cornish language word for basin.

The sixth century Welsh Celtic Saint Nectan was believed to have had his hermitage above the waterfall. According to legend he rang a silver bell in times of stormy weather to warn shipping of the perils of the rocks at the mouth of the Rocky Valley. Though legends abound, no evidence exists to substantiate Nectan's presence here.

Saint Nectan's Kieve is believed by some to be a sacred place. As such, numerous ribbons, crystals, photographs, inscriptions, prayers and other devotions now adorn the foliage and rock walls near to the waterfall.