In 1800 the arrondissements of Alençon, Argentan, Domfront and Mortagne-au-Perche were established. The arrondissements of Domfront and Mortagne-au-Perche were disbanded in 1926, and Then, Mortagne-au-Perche was restored in 1942.[3]
The borders of the arrondissements of Orne were modified in January 2017:[4]
11 communes from the arrondissement of Alençon to the arrondissement of Argentan
one commune from the arrondissement of Alençon to the arrondissement of Mortagne-au-Perche
nine communes from the arrondissement of Argentan to the arrondissement of Alençon
49 communes from the arrondissement of Argentan to the arrondissement of Mortagne-au-Perche
five communes from the arrondissement of Mortagne-au-Perche to the arrondissement of Alençon