Ermont (French pronunciation: [ɛʁmɔ̃]) is a commune in the Val-d'Oise department, in the northern suburbs of Paris, France. It is located 17.2 km (10.7 mi) from the center of Paris. It has around 28,000 inhabitants, which makes Ermont one of the most important cities in Val d'Oise. Ermont has experienced rapid urbanization thanks to railway transport and industrialization, with the population of Ermont being just 9000 after the Second World War to now more than 28,000.