The name of the river is "Mae Si" ([sīː]) in the Isan and Lao languages of the region, being transliterated as "Chi" in Bangkok-Thai.

[1] The river rises in the Phetchabun mountains, then runs east through the central Isan provinces of Chaiyaphum, Khon Kaen, and Maha Sarakham, then turns south in Roi Et, runs through Yasothon and joins the Mun in the Kanthararom district of Sisaket Province.

This began in 1718 when the first king of the left bank Kingdom of Champasak, King Nokasad, sent a group of some 3,000 subjects led by an official in his service to found the first settlement in the Chi River valley—and indeed anywhere in the interior of the Khorat Plateau—Muang Suwannaphum in present-day Roi Et Province[3] (a history recorded and remembered, largely in terms of the struggle to expand wet-rice cultivation in the river valley).

Their descendants are now regarded as a separate ethnic group from the Lao to the north and the central Thai to the southwest.

It was an action-drama TV series that aired from March 14 to April 25, 2018, remake from namesake film in 1969 (starred by Mitr Chaibancha and Petchara Chaowarat).