Ermont is located in Paris city, France at the 48.99, 2.258 coordinates. Distance from Ermont to other cities. are listed below, click on the city name to find distance between. Distance from Ermont to Cergy-Pontoise 14 km, to Saint-Quentin-en-Yvelines 30 km, to Boulogne-Billancourt 17 km. The green marker indicates the location of Ermont.