Tonkin (historically), also spelled Tongkin, Tonquin or Tongking, is the northernmost part of Vietnam, south of China's Yunnan and Guangxi Provinces, east of northern Laos, and west of the Gulf of Tonkin.
Tonkin (historically), also spelled Tongkin, Tonquin or Tongking, is in the Red River Delta Region of northern Vietnam. It is south of the Northeast Region of Vietnam, and of Yunnan and Guangxi Provinces of China; east of northern Laos; and west of the Gulf of Tonkin.