Nam Sam River

Chu River (name in

Vietnam Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...

, ), also known as the Nam Sam River or Nam Xam River (name in

Laos Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...

), is the largest tributary of Mã River. It originates from Houa peak at 2062m near

Xam Neua Xam Neua (, , sometimes transcribed as ''Sam Nuea'' or ''Samneua'', literally 'northern swamp'; ), is the capital of Houaphanh Province, Laos. History After fleeing from Phrae, deposed king Phiriya Thepphawong escaped from Northern Thailand to ...

town,

Houaphanh Province Houaphanh province (, , Romanization of Lao: ''Houaphan'' also ''Huaphan'') is a province in eastern Laos. Its capital is Xam Neua. Houaphanh province covers an area of . It is bordered by Vietnam to the north, east, and southeast, Xiangkhoua ...

in eastern Laos and travels east to meander through the Nghệ An and

Thanh Hóa Thanh Hóa () is the capital of Thanh Hóa Province. The city is situated in the east of the province on the Ma River (Sông Mã), about 150 kilometers (93 miles) south of capital Hanoi and 1560 kilometers (969 miles) north of Ho Chi Minh Cit ...

provinces of Vietnam. It joins Mã River on the left in Thiệu Hóa. The river is 325 km long (165 km in Laos and 160 km in Vietnam) with a

drainage area A drainage basin is an area of land in which all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, th ...

of about 7,580 km² (4,570 km² in Laos and 3,010 km² in Vietnam). Rivers of Laos Rivers of Nghệ An province Rivers of Thanh Hóa province International rivers of Asia Geography of Houaphanh province Rivers of Vietnam {{Vietnam-river-stub