St John (parish: Cornish: Pluwjowan, village: Cornish: S. Jowan)[1] is a coastal civil parish and a village in south-east Cornwall, England, United Kingdom, 3 miles (4.8 km) south of Saltash and 1.5 miles (2.4 km) south-west of Torpoint.

[3] To the north, the parish is bordered by St John's Lake and to the south by the sea.

A few hundred metres north of St John village is an area of high ground called Vanderbands, the site of an Iron Age castle mentioned by John Norden (an English topographer who wrote a series of county histories) in his description of Cornwall published in 1728.

Part of the land designated as St John's Lake SSSI is owned by the Ministry of Defence.

[6] The historic records for much of this area were kept at Mount Edgcumbe House but were destroyed during the war[which?