Communauté urbaine Grand Paris Seine et Oise

The Communauté urbaine Grand Paris Seine et Oise is the communauté urbaine, an intercommunal structure, covering the western suburbs of Paris. It is located in the Yvelines department, in the Île-de-France region, northern France. It was created in January 2016 by the merger of the previous communautés d'agglomération Mantes-en-Yvelines, Deux Rives de la Seine, Poissy-Achères-Conflans-Sainte-Honorine, Seine & Vexin and the communautés de communes Coteaux du Vexin and Seine-Mauldre. Its population was 411,100 in 2014. Its seat is in Aubergenville.

The communauté urbaine consists of the following 73 communes: