The term "Zomia" has begun to become established in the fields of geography and historical studies only in recent decades. It largely defines the geographic area of the highlands of Southeast Asia, a vast region at an altitude of 300 meters and above, that spans five countries (Vietnam, Cambodia, Laos, Thailand, and Burma) and four provinces of southern China.

About one hundred million people live there, belonging to minority populations and forming a complex ethnic and cultural mosaic. It was, and to some extent remains, a "zone of fracture" of state formation, much like the Caucasus and the Balkans have historically been.

It has been inhabited for at least two millennia by successive waves of refugees fleeing from state cores, the "rice lords" of the valleys — due to invasions, slave raids, epidemics, and forced labor — seeking refuge in this inaccessible zone that encouraged the divergence of dialects, customs, religious beliefs, and identities.