[1] It is in the former administrative district of Kerrier and is bounded to the south by the Helford River, to the east by the sea, and to the west by Constantine parish.
[4] The parish is entirely rural and, as well as Mawnan Smith, includes the hamlets of Carlidnack, Bareppa, Penwarne, Helford Passage, Maenporth and Durgan.
Marine species found here include Mytilus mussels, various seaweeds and sea sponges, such as Botryllus schlosseri.
It is suggested that Mawnan takes its name from a 6th-century Saint Maunanus, who was probably a Breton monk who landed here about AD 520.
There is a Roman Catholic church dedicated to St Edward the Confessor in Old Church Road, which was completed in 1965. Notable country houses in the parish include Bosloe, Bosveal, Carwinion, Penwarne, Nansidwell (c. 1905 by Leonard Stokes), Heyle and Bareppa.