Nearly all speakers of Kam-Sui languages originate in the Qiandongnan (Dong) and Qiannan (Sui, Then, Mak, Ai-Cham) Prefectures of Guizhou, as well as the prefecture-level cities of Hechi (Mulam and Maonan) and Guilin (Chadong) in northern Guangxi.
Small groups of Kam and Sui speakers also reside in Tuyên Quang Province, Vietnam, in the villages of Đồng Mộc and Hồng Quang, respectively.