Mayenne is a landlocked department in northwest France named after the river Mayenne. Mayenne is part of the administrative region of Pays de la Loire and is surrounded by the departments of Manche, Orne, Sarthe, Maine-et-Loire, and Ille-et-Vilaine.

The Mayenne is a 202.3 km (125.7 mi) long river in western France, principally located in the French region of Pays de la Loire. Together with the river Sarthe and its tributary the Loir it forms the Maine, which is a tributary to the Loire.