ST SERVAN, a town of western France, in the department of Ille-et-Vilaine, on the right bank of the Rance, south of St Malo, from which it is separated by the Anse des Sablons, a creek 1 m. wide (see St Malo). Pop. (1906) 9765. It is not enclosed by walls, and with its new houses, straight wide streets and numerous gardens forms a contrast to its neighbour. North of the town there is a wet-dock, 27 acres in extent, forming part of the harbour of St Malo. The creek on which it opens is dry at low water, but at high water is 30 to 40 ft. deep. The dock is used chiefly by coasting and fishing vessels, a fleet starting annually for the Newfoundland cod-fisheries. Two other ports on the Rance, south-west of the town at the foot of the tower of Solidor, are of small importance. This stronghold, erected towards the close of the 14th century by John IV., duke of Brittany, for the purpose of contesting the claims to the temporal sovereignty of the town of Josselin de Rohan, bishop of St Malo, consists of three distinct towers formed into a triangle by loop-holed and machicolated curtains. To the west St Servan terminates in a peninsula on which stands the “ cité,” inhabited by work-people, and the “ fort de la cité ”; near by is a modern chapel which has replaced the cathedral of St Peter of Aleth, the seat of a bishopric from the 6th tovthe 12th century. The parish church is modern (1742–1842). St Servan has a communal college. It carries on steam-sawing, boat-building, rope-making and the manufacture of ship's biscuits. .

The “ Cité ” occupies the site of the city of Aleth, which at the close of the Roman empire supplanted Corseul as the capital of the Curiosolites. Aleth was a bulwark of Druidism in those regions and was not Christianized till the 6th century, when St Malo became its first bishop. On the removal of the bishopric to St Malo Aleth declined and was almost destroyed by St Louis in 1235; the houses that remained standing became the nucleus of a new community, originating from St Malo, which placed itself under the patronage of St Servan, apostle of the Orkneys. It was not till the Revolution that St Servan became a separate commune from St Malo with a municipality and police of its own.