Chi River

Not to be confused with the Chi River tributary to the Huai in China.

Chi River
River
Ferry over the Chi River
Source
- elevation	30 m (98 ft)
Mouth
- location	Mun river, Sisaket Province
- elevation	110 m (361 ft)
Length	765 km (475 mi)
Basin	49,480 km2 (19,104 sq mi)
Discharge	for Yasothon
- average	290 m3/s (10,241 cu ft/s)
- max	3,960 m3/s (139,846 cu ft/s)
Map of the Mun River watershed showing the Chi River

The Chi River (Thai: แม่น้ำชี, RTGS: Maenam Chi, IPA: [mɛ̂ːnáːm tɕʰīː]) is the longest river in Thailand; it extends 765 km, but carries less water than the second longest river, the Mun. In the Isan dialect of this region, and also in the adjacent language Lao, the name of the river is actually pronounced "Nam Si" ([sīː]) but the transliteration Chi reflects Bangkok-Thai.

The river rises in the Phetchabun mountains, then runs east through the central Isan provinces of Chaiyaphum, Khon Kaen and Maha Sarakham, and turns south in Roi Et, running through Yasothon to meet the Mun in Kanthararom district of Sisaket Province. The river carries approximately 9,300 cubic kilometres of water per annum. It is riddled with leeches.

The river was an 18th century migration route for the expansion of the ethnic Lao people over the Isan plateau (a history recorded and remembered, largely in terms of the struggle to expand wet-rice cultivation in the river valley), who are now regarded as a separate ethnos from the Lao to the North or the central Thai to the South-West.

Coordinates: 16°13′N 103°37′E / 16.21°N 103.62°E / 16.21; 103.62