The 3 arrondissements of the Seine-Maritime department are: 1. * Arrondissement of Dieppe, (subprefecture: Dieppe) with 343 communes. The population of the arrondissement was 237,203 in 2016. 2. * Arrondissement of Le Havre, (subprefecture: Le Havre) with 149 communes. The population of the arrondissement was 387,520 in 2016. 3. * Arrondissement of Rouen, (prefecture of the Seine-Maritime department: Rouen) with 216 communes. The population of the arrondissement was 631,032 in 2016.