The town was founded in the 12th century after a vow by
William the Conqueror. It was home to a fortress, which was razed to the ground in 1623 by order of King
Louis XIII. During
World War II, after the liberation of the area by
Allied Forces in 1944, engineers of the
Ninth Air Force IX Engineering Command began construction of a combat
Advanced Landing Ground outside of the town. Declared operational on 10 August, the airfield was designated as "
A-28", it was used by the
368th Fighter Group which flew
P-47 Thunderbolts until early September when the unit moved into Central France. Afterward, the airfield was closed.
Frantz Fanon practiced psychiatry in Pontorson in the early 1950s. In 1973 Pontorson absorbed seven former communes: Ardevon,
Beauvoir (re-established in 1989), Boucey, Cormeray, Curey, Les Pas and Moidrey. On 1 January 2016, the former communes of
Macey and
Vessey were merged into Pontorson. In 1990, Pontorson twinned with the town of
Highworth in
England. ==Population==