Cergy Population and Area (Val-d'Oise)
Largest city in France 2026: up-to-date figures for Cergy (Val-d'Oise)
Cergy: Population and Area
With 71,250 inhabitants (INSEE total population in force on January 1, 2026), Cergy is the 74th most populous town in France in 2026 and the 2nd most populous in the Val-d'Oise department, out of 183 communes. It covers 12 km² (16,330th largest area in France, 21st largest in the department), with a population density of 6,116 inhabitants per km², or 56 times the national average (110 inhabitants/km²), which ranks it 102nd in France for density.
Cergy is located in the Val-d'Oise department (95), in the Île-de-France region, where it ranks 20th by population out of 1,266 communes. The most populous town in the Val-d'Oise department is Argenteuil (106,546 inhabitants); the department is home to 1,290,942 people over 1,246 km².
See the full ranking of communes in the Val-d'Oise department and the regional ranking: largest city in Île-de-France.
Towns of similar size in the Val-d'Oise department: Argenteuil (pop. 106,546), Sarcelles (pop. 59,385), Garges-lès-Gonesse (pop. 41,893), Franconville (pop. 37,896).
Sources: INSEE, official population figures in force on January 1, 2026 (total population); areas: IGN / Observatoire des territoires; INSEE code 95127. Rankings are calculated across the 34,858 communes of metropolitan and overseas France in our database.
Cergy, heart of the Cergy-Pontoise new town
The second-largest town in the Val-d'Oise by population, behind Argenteuil, Cergy owes its size to the new town of Cergy-Pontoise, created from the late 1960s onward to organize the growth of Île-de-France. It houses the offices of the Val-d'Oise prefecture, although the department's official capital remains the neighboring town of Pontoise.
A young student city
A village in the Oise valley until the 1970s, Cergy saw entire neighborhoods spring up within a few decades, including the Axe Majeur, a monumental work by Dani Karavan, and the leisure park built on former gravel pits. Universities and grandes écoles attract thousands of students, making it one of the youngest major cities in France. Linked to Paris by the RER A and commuter trains, the town keeps gaining residents, with the density of a mid-sized city and vast green spaces along the Oise.