Cergy-Pontoise

Administrative centre of the département of Val-d'Oise, France, 30 km/19 mi northwest of Paris, at the confluence of the rivers Viosne and Oise; population (1990) 159,000. Pontoise changed its name after a massive expansion programme; it was accorded new town status in 1965. It has metallurgical and chemical industries, a university, and many offices and light industries. It has a 12th-century cathedral and became an episcopal see in 1966.

Pontoise was the capital of the historical region of Le Vexin Français. In 1437, during the Hundred Years' War, English soldiers captured the town by stealth by wearing white clothing which camouflaged them in the snow.

The Impressionist artist Camille Pissarro lived here for a while and did some of his work in the town, as did Paul Cézanne, who often stayed with him.