The canton of Lagny-sur-Marne is a French administrative division, located in the arrondissement of Torcy, in the Seine-et-Marne département (Île-de-France région). Demographics Composition At the French canton reorganisation which came into effect in March 2015, the canton was expanded from 4 to 14 communes: Carnetin Chalifert Chanteloup-en-Brie Conches-sur-Gondoire Dampmart Gouvernes Guermantes Jablines Lagny-sur-Marne Lesches Montévrain Pomponne Saint-Thibault-des-Vignes Thorigny-sur-Marne See also Cantons of the Seine-et-Marne department Communes of the Seine-et-Marne department References Lagny sur marne