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.^[1] Its area is 504.7 km². Its population was 417,556 in 2018.^[2] Its seat is in Aubergenville.^[3]

Grand Paris Seine et Oise
Communauté urbaine
Location within the Yvelines department
Country	France
Region	Île-de-France
Department	Yvelines
No. of communes	73
Established	2016
Seat	Aubergenville
Area	504.7 km2 (194.9 sq mi)
Population  (2018)	417,556
• Density	827/km2 (2,140/sq mi)
Website	gpseo.fr