The Nanxi River (Chinese: 南溪河; pinyin: Nánxī Hé), also known as the Nậm Thi River in Vietnamese or Namiti, is a tributary of the Red River located in China's Yunnan province. It is a border river of Lào Cai, Vietnam, and Hekou, China.
The Chinese portion of the Yunnan–Vietnam Railway was built partly along the Nanxi River valley from 1906 to 1910, linking the city of Kunming with the Vietnamese capital, Hanoi. The mountainous terrain of the Nanxi River Valley posed special difficulties for the railway's construction; this, along with the endemic nature of malaria in the area, led to the deaths of at least 10,000 workers in the valley. Today, the Nanxi River is known as a destination for white water rafting.
- Le petit train du Yunnan: Embarquement. Dominique Roland et Stéphanie Déro. Routard.com (Cyberterre). 2003-08-05.
- The Railway Conquest of the World. Forgotten Books. ISBN 1-4400-5980-2. pp.302-304.
- to the construction of a bridge across the Nậm Thi river linking Lào Cai Province in Vietnam with Hekou Province in China.
- Translations on People's Republic of China - Numéros 492 à 502 - Page 99 United States. Joint Publications Research Service - 1979 "Hekou is a peaceful beautiful border town at the junction of the Hong and Nanxi rivers, border rivers between China and Vietnam. However, the atmosphere of peace and tranquility in this border town was completely spoiled after the "
- Little, Archibald John (2010), Little, Alicia (ed.), Across Yunnan: A Journey of Surprises, Cambridge University Press, p. 86, ISBN 1108014097 (originally published 1910)
- Le chemin de fer du Yunnan et les Centraliens - 1902-1910.
- Archives of the French Foreign Ministry, Chine, Nouvelle série, vols.498-502.
- Potential railway world heritage sites in Asia and the Pacific. Robert Lee. University of Western Sydney, Macarthur. 11 Feb 2003.