The 3 arrondissements of the Mayenne department are:[1]
- Arrondissement of Château-Gontier, (subprefecture: Château-Gontier-sur-Mayenne) with 76 communes. The population of the arrondissement was 73,211 in 2021.
- Arrondissement of Laval, (prefecture of the Mayenne department: Laval) with 34 communes. The population of the arrondissement was 114,674 in 2021.
- Arrondissement of Mayenne, (subprefecture: Mayenne) with 130 communes. The population of the arrondissement was 118,048 in 2021.