International audienceBased on different research in two foreign disciplines (geography and psychopathology) this article focuses on a poorly documented part of today's youth population: 15 to 25 years old young people living in sparsely populated areas. In France and in the Republic of Ireland, where our cases studies are set, we explain how young people's mobility is nowadays pluralist. We show that mobility of young people, often unexpected, can be qualified as circular, sedentary or close to roving life. It originates from their territoriality and in the forms which they define their trajectory.En s'appuyant sur des éléments de réflexion issus de plusieurs recherches dans des disciplines peu habituées à travailler ensemble, la géographi...