St Mewan (Cornish: Sen Mewen) is a civil parish and village in south Cornwall, England, United Kingdom.

St Mewan parish also includes the settlements of Hewas Water, Sticker, Trelowth, Trewoon, and most of Polgooth.

Local legend suggests that the original builders were prevented from raising it higher by the devil, who threw down their stones each night.

It is a tor exposure of quartz-topaz-tourmaline rocks that has been designated a Site of Special Scientific Interest (SSSI) for its geological characteristics.

[10] St Mewan Beacon was studied by Cornish mining engineer and mineralogist Joseph Henry Collins who published an account of it in 1914.