Situated at the beginning of the Oise loop, the village of Eragny stands on the north facing cliff overlooking the Oise. At the end of the 19th Century Eragny had fewer than 500 inhabitants, living chiefly from agriculture and market gardening. The arrival of the railway prompted the exploitation of a limestone quarry which had until then served only local needs.
In the 20th Century the establishment of a paper mill constituted the sole significant industrial activity in the area, giving Eragny a certain degree of prominence. This paper mill, the first commercial enterprise to be set up in the new activity zone, gave its name to the district in which a beautiful hall housed the paper presses. This hall has been transformed into an exhibition room.
The development of Greater Cergy-Pontoise at the end of the 1960s transformed the village. New districts sprang up on the plateau, with the village below. They were created along the lines of « town-garden », with pedestrian and automobile routes kept distinct and separate. These districts consist largely of small apartment blocks and individual houses. They include communal facilities, such as schools and lycées, notably the Lycée Professionnel Auguste Escoffier, whose sections focused on the culinary arts have gained a high reputation in the region.