In view of the impossible differentiation between geographic and ethnographic knowledge during the colonial times it is necessary to abandon the epistemological approach and to reconsider the emergence of this knowledge in the light of colonial contexts where the division of the two disciplines prevailing in France is unknown. This article examines the « invention » of the South-Indo-Chinese Highlands in the colonial discourses. It reveals the existence of a specific colonial configuration in which geography and ethnology are the two sides of a same knowledge (of men and environment) that aims at giving these spaces a visibility in order to penetrate their heart.