The source is in the foothills of Mont des Avaloirs at an altitude of 961 feet (293m); from there the river runs from east to west until it reaches Sept-Forges, at which point it turns to the south.
Departments and towns along the river include: It is featured prominently in the video game Call of Duty 3.
The river was used by barges carrying up to 130 tonnes, and the principal traffics were construction materials (wood and stone), coal from the mines of L'Huisserie, grain, fruit and vegetables.
At this time it was planned to build a watershed canal north from Mayenne to the tidal river Orne at Caen, but the project was abandoned as railways became the preferred carrier of freight.
[2] In spite of abundant precipitation, the flow of the Mayenne is irregular because of the impermeability of the sandstone, granite, and schist which form its drainage basin.