The Soi River ( vi, Sông Sỏi) is a tributary of the
Red River in northern
Vietnam
Vietnam or Viet Nam ( vi, Việt Nam, ), officially the Socialist Republic of Vietnam,., group="n" is a country in Southeast Asia, at the eastern edge of mainland Southeast Asia, with an area of and population of 96 million, making i ...
. It flows through
Đồng Hỷ District,
Thái Nguyên Province
Cài () is a Chinese-language surname that derives from the name of the ancient Cai state. In 2019 it was the 38th most common surname in China, but the 9th most common in Taiwan (as of 2018), where it is usually romanized as "Tsai" (based on ...
. It originates from Mount Bo Cu at around 400 metres above sea level, in upland communes. The river has a total length of 38 km and has a basin area of 303 km2.
Rivers of Thái Nguyên province
Rivers of Vietnam
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