The county of Perche was a medieval county lying between Normandy and Maine. It was held by a continuous line of counts until 1226. One of these, Geoffroy III, would have been a leader of the Fourth Crusade had he not died before the assembled forces could depart. The county then became a possession of the crown, which removed part of it to create the county of Alençon. After 1325, both counties were generally held by a member or members of a cadet line of the House of Valois. Upon the death without children of the last Duke of Alençon in 1525, it returned to the crown, and was granted only sporadically thereafter.

Lords of Mortagne, lords of Nogent-le-Rotrou and viscounts of Châteaudun

The lords of Perche were originally titled lords of Mortagne-au-Perche, until Rotrou III adopted the style of count of Perche in 1126, thus uniting the lordship of Mortagne-au-Perche, the viscountcy of Châteaudun and the lordship of Nogent-le-Rotrou in the countship of Perche and Montagne.

Lords of Mortagne

House of Rorgonid

Here after, the title is merged with the viscount of Châteaudun and the lord of Nogent-le-Rotrou.

Lords of Nogent-le-Rotrou

House of Nogent-le-Rotrou

Here after, the title is merged with the viscount of Châteaudun and the lord of Mortagne-au-Perche

Viscounts of Châteaudun

House of Châteaudun

Lords and counts of Perche and Mortagne

House of Châteaudun

Here after, the title is separated in count of Perche and count of Mortagne.

Counts of Perche

House of Châteaudun

Here after the county returned to the royal domain. The title of count of Perche was granted anew by the king to members of the House of Maine and the House of Châteaudun.

House of Valois

The county was confiscated by the crown between 1474 and 1478, but was then returned to the family. After the death of Margaret of Navarre the fief went to the royal domain. Henceforth the title of duke of Perche was granted by the king from time to time.

Dukes of Perche

House of Valois

House of Bourbon

English title