The four subspecies are geographically separated. The Tonkin black crested gibbon ("Nomascus concolor concolor") occurs in southern China (southwestern Yunnan) and northern Vietnam (Lào Cai, Yên Bái, Sơn La, and Lai Châu provinces), between the Black and Red Rivers. The West Yunnan black crested gibbon ("N. c. furvogaster") occurs in a small area near the Burma border, west of the Mekong, in southwestern Yunnan, southern China. The Central Yunnan black crested gibbon ("N. c. jingdongensis") occurs in a small region around the Wuliang Mountains, between the Mekong and Chuanhe rivers in west-central Yunnan. The Laotian black crested gibbon ("N. c. lu") occurs in northwestern Laos in an isolated population on the east bank of the Mekong in Laos.