[1] It is located at the northeastern tip of Lake Neuchâtel at an elevation of 455 meters, and, as of 2004[update], 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 Métaux Précieux SA Métalor and TAG Heuer watches.

The blazon of Marin-Epagnier's coat-of-arms is: "Sable, a Lion rampant or langued and armed Gules".

La Tène was the name of the lakeside area south of Epagnier, at the eastern end of the Lake Neuchâtel.