25 km long between Fromentine (municipality of La Barre-de-Monts) to the north and Sion-sur-l'Océan (municipality of Saint-Hilaire-de-Riez) to the south, its width does not exceed 2.3 kilometres (1.4 miles).

It also impacts on the town planning of coastal municipalities such as those of Saint-Jean-de-Monts and Notre-Dame-de-Monts by separating the waterfronts from their town centres with wooded avenues forming a "greenway" of a hundred meters width.

[1] The national forest of Pays-de-Monts was planted at the end of the 19th century under the Second Empire as part of a broader process of fixing the dunes and draining the marshes for cultivation.

According to Natura 2000, the forest is part of a larger geographical framework also encompassing the marshes of the Marais Breton, the Bay of Bourgneuf, and the island of Noirmoutier.

[2] This same geographical area was designated on February 2, 2017 as a Wetland of International Importance under the Ramsar Convention.