The town takes its name from the Celtic saint Saint Maudez (Mawe), who may have come from Ireland but is mainly venerated in Brittany. A name: 'Musidum' in Roman times, has subsequently been applied to St. Mawes, although the source is dubious.
St Mawes lies within the Cornwall Area of Outstanding Natural Beauty (AONB). Almost a third of Cornwall has AONB designation, with the same status and protection as a National Park.
St Mawes Castle is a well-preserved coastal fortress from the time of Henry VIII, built to counter the invasion threat from the Continent. Charles Henderson, writing in 1925, says of St Mawes, "an ancient fishing town which in late years has assumed the different and more sophisticated character of a watering place". The seal of St Mawes was Az. a bend lozengy Or between a tower in the sinister chief Arg. and a ship with three masts the sail furled in the dexter base of the second, with the legend "Commune Sigillum Burgi de St. Mawes al Mauditt.
Just outside the town is a closed British Leyland garage on Polvarth Road which retains the British Leyland logo on a hoarding outside.
