St Michael's Mount (, meaning "grey rock in the woods", also known colloquially by locals as simply the Mount) is a tidal island off the Mount's Bay coast of Cornwall, England, United Kingdom. It is a civil parish and is united with the town of Marazion by a man-made causeway of granite setts, passable between mid-tide and low water. In prehistoric times, St Michael's Mount may have been a port for the tin trade, and Gavin de Beer made a case for it to be identified with the "tin port" Ictis/Ictin mentioned by Posidonius.