The County of Mortain was a medieval county in the Duchy of Normandy in France centered on the town of Mortain, disputed between France and England during parts of the Hundred Years' War. A choice landholding, usually either kept within the family of the duke of Normandy (or the king of France) or granted to a noble in return for service and favor. This was the main reason Mortain had so many counts and from different lineages, as shown below, during its long history.

Norman counts of Mortain

• Mauger of Corbeil (9881032)

• (10321048)

• Robert, Count of Mortain (10491104)

• William, Count of Mortain (11041106)

• Robert II of Vitré (11061112)

• Stephen of England (11121135)

• Eustace IV of Boulogne (11351141)

• Geoffrey of Anjou (11411144)

• William of Blois (11541159)

• Vacant

• Marie of Boulogne and Matthew of Alsace (11671173)

• Vacant

• John later King of England (11891199)

• Ida, Countess of Boulogne and Renaud de Dammartin (12041216)

Matilda II of Boulogne (12161245) and...

• Philip Hurepel (12161233)

• Afonso III of Portugal (12381245)

Jeanne de Dammartin (12451251) and ..

• Walter of Châtillon (12451250)

• Vacant

• Joan II of Navarre (13281349)

• Vacant

• Peter d'Évreux (14011412)

Catherine of Alençon (14121416) (his widow) and..

• Louis, Duke of Guyenne (14121413)

• Louis VII of Bavaria, Duke of Bavaria-Ingolstadt (14131416)

Jean Dunois (14161417) and..

• Charles of Le Maine (14161417)

• Charles of Valois, Duke of Berry (14161417)

English counts of Mortain

• Edward Holland (14181419)

• Thomas Langholme (1419?)

• John of Lancaster, 1st Duke of Bedford (?1435)

• Edmund Beaufort, 2nd Duke of Somerset (14351449)

French counts of Mortain

• Charles of Le Maine (14491472)

• Charles IV, Duke of Anjou (14721481)

• Royal Domain

• Louis II, Duke of Montpensier (15291582)

• Francis, Duke of Montpensier (15821592)

• Henri de Bourbon, duc de Montpensier (15921608)

Marie de Bourbon, duchesse de Montpensier (16081627) and..

• Gaston de France, duc d'Orléans (16261660) (her widower)

• Anne Marie Louise d'Orléans, duchesse de Montpensier (16601693)

• Philippe de France, duc d'Orléans (16931701)

• Philippe II d'Orléans, duc d'Orléans (17011723)

• Louis d'Orléáns, duc d'Orléans (17231752)

• Louis Philippe I d'Orléans, duc d'Orléans (17521785)

• Louis Philippe II d'Orléans, duc d'Orléans (17851786)

• Royal Domain

• Henri d'Orléans, comte de Paris, duc de France (19842019) (never recognised it as his main title)

Notes