It is located at the northeastern tip of Lake Neuchâtel. It is within the district of Neuchâtel in the canton of Neuchâtel. It has an elevation of 455 meters, and, as of 2004, a population of 3,925 people. It lies close to Biel, at the boundary between French- and German-speaking regions, and at a knot of highways. Marin Epagnier has attracted numerous administrative offices and workshops of the micromechanics, electronics, and watchmaking industries, such as Bertolucci, Waltham, and TAG Heuer watches.
The Iron Age archaeological site of La Tène is within Marin-Epagnier's communal boundaries. (See also La Tène culture.) La Tène is a village located at the eastern end of the Lake Neuchâtel (Lac de Neuchâtel), a lake in Switzerland. It is now a leisure area within the commune of Marin-Epagnier in Canton Neuchâtel. La Tène has a sandy beach, unique in Switzerland.