St Mawes was a rotten borough in Cornwall, England.
The borough consisted of the manor of St Mawes, a decayed fishing port and market town in the west of Cornwall.
The right to vote rested with the portreeve and "resident burgesses or free tenants", making it essentially a scot and lot borough (there were 87 voters in 1831), but the control of the "patron" was entirely secure.
In practice the patron always worked in close collusion with the Crown, and the members returned were generally court nominees throughout the borough's existence.
In the 1760s the Boscawen family (the Viscounts Falmouth) were considered to have the main influence over the choice of one member[1] and Robert Nugent over the other;[2] by the time of the Great Reform Act, the patronage had passed to the Marquess of Buckingham.