Seine-et-Marne's a French department, named after the Seine and Marne rivers, and located in the Île-de-France region. History Seine-et-Marne's one of the original 83 departments, created on March 4, 1790 during the French Revolution in application of the law of December 22, 1789. It'd previously belonged to the former province of Île-de-France. Geography Seine-et-Marne forms a part of the Île-de-France region; the department forms the eastern half of the region and because of… (More on Seine-et-marne)