Mortain is a small town in the département of La Manche, France, the chief town of an arrondissement and seat of a sub-prefect. It is beautifully situated on a rocky hill rising above the gorge of the Cance, a tributary of the Sélune. The parish church of St Evroult is a magnificent example of the transitional style of the early 13th century. Close to the town is the Abbaye Blanche, founded as a Benedictine convent in 1105 and soon afterwards affiliated to Citeaux. The church is a perfect example of a Cistercian monastic church of the late 12th century, and portions of the 12th-century cloisters also survive. The population is between 2000 and 3000.

In August 1944, Mortain was the site of a battle between the German and Allied forces.

Mortain was, in the Middle Ages, the head of an important comté, reserved for the reigning house of Normandy. Around 1027 it was established for Robert, who was probably an illegitimate son of Richard I of Normandy. He was succeeded by William Warlenc ("the waning") who was probably his son. In or about 1049 Duke William took it from William Warlenc and bestowed it on his half-brother, Robert, thenceforth known as "count of Mortain," whose vast possessions in England after the Conquest (1066) gave name to "the small fees of Mortain," which owed less feudal service than others. Robert was succeeded as count by his son William, Count of Mortain, who rebelled against Henry I, was captured at the battle of Tinchebrai (1106) and forfeited his possessions. Some years later, Henry bestowed the comtéship on his nephew Stephen, who became king in 1135. On Stephen?s death (1154) his surviving son William became count of Mortain, but when William died childless in 1159 the title was resumed by Henry II. On the accession of Richard I (1189) he granted it to his brother John, who was thenceforth known as count of Mortain till he ascended the throne (1199). With his loss of Normandy the comté was lost, but after the recapture of the province by the House of Lancaster, Edmund Beaufort, a grandson of John of Gaunt, was created count of Mortain and so styled till 1441, when he was made earl of Dorset.

Adapted and updated from a 1911 encyclopedia.