The organisation named Communauté de Communes du Val d'Oust et de Lanvaux is a group of municipalities in the department of the Morbihan, in Brittany. The total population of this intermunicipal organisation is 20099 inhabitants, spread across a surface area of 322.81 km². The population density is 89 inhabitants/km². The altitude varies between 5 metres and 163 metres. The Communauté de Communes du Val d'Oust et de Lanvaux public intermunicipal cooperation establishment comprises the 15 municipalities listed below.