In Vietnam, the abundant rainfall has resulted in a vast network of rivers and streams, numbering approximately 2,360 rivers and canals of various sizes. Along the coastline, there are around 23 kilometers with river mouths, and statistics show there are 112 river mouths flowing into the sea. The major rivers in Vietnam typically originate from outside the country, with their mid and lower reaches flowing through Vietnamese territory. Most rivers in Vietnam flow in a Northwest to Southeast direction, emptying into the South China Sea.
The Longest Rivers in Vietnam
1. Dong Nai River
The Dong Nai River is the longest inland river in Vietnam.
As the longest inland river in Vietnam, the Dong Nai River originates from the Langbiang Plateau (Lam Dong) with a total length of 586 km. With an enormous water discharge, it is a significant source of hydroelectric power for the Dong Nai Hydropower Plant. The river flows through the provinces of Lam Dong, Dak Nong, Binh Phuoc, Dong Nai, Binh Duong, and Ho Chi Minh City, with over 437 km within Vietnam and a basin area of 38,600 km². If measured from the source of the Da Dang River, it is 586 km long, while from the confluence with the Da Nhim River below Pongour Falls, it is 487 km long. The Dong Nai River empties into the South China Sea at the Can Gio District.
The upper main stream of the Dong Nai River is known as the Da Dang River. It starts from the Lam Vien Plateau, winding in a Northeast to Southwest direction, emerging from the mountains to the Tà Lài plain (Tan Phu District, Dong Nai Province). The river serves as a natural boundary between Dak R’Lap (Dak Nong) and Bao Lam – Cat Tien (Lam Dong), between Cat Tien and Bu Dang (Binh Phuoc) – Tan Phu, and between Tan Phu and Da Teh.
After meeting the Be River, the Dong Nai River forms a natural boundary between Dong Nai (Vinh Cuu) on the left bank – east side and Binh Duong (Tan Uyen) on the right bank – west side. In the Uyên Hưng ward of Tan Uyen town, Binh Duong province, the Dong Nai River flows in a North-South direction, wrapping around Tan Uyen Island and Cu Lao Pho. Cu Lao Pho on the Dong Nai River was a prosperous area for the Minh Huong community before this land became an official administrative unit of Đàng Trong in 1698.
The Dong Nai River flows through Bien Hoa City and then along the boundary between Dong Nai (Long Thanh, Nhon Trach) and Ho Chi Minh City (District 9, District 2, District 7, Nha Be, Can Gio), between Ba Ria – Vung Tau (Phu My) and Ho Chi Minh City (Can Gio). The lower main stream of the Dong Nai River, from the confluence with the Saigon River to the bifurcation into Soai Rap and Long Tau, is commonly referred to as the Nha Be River. Historically, this river was known as “Phuoc Binh”.
2. Da River
The main stream of the Da River enters Vietnam at Mu Ca, Muong Te.
The Da River, also known as the Bo River or Da Giang, is the largest tributary of the Red River. It has a length of 910 km (some sources state 983 km) and a basin area of 52,900 km². The main stream originates from Mount Wu Liang, Yunnan Province, China, flowing in a Northwest to Southeast direction before merging with the Red River in Phu Tho. The section of the river in Vietnam is 527 km long (some sources state 543 km). The starting point is the Vietnam-China border at Muong Te (Lai Chau). The river flows through the Northwestern provinces of Vietnam, including Lai Chau, Dien Bien, Son La, Hoa Binh, and Phu Tho (dividing Thanh Thuy District, Phu Tho from Ba Vi, Hanoi). Its endpoint is at the Hong Da junction in Tam Nong District, Phu Tho Province.
The main stream of the Da River enters Vietnam at Mu Ca, Muong Te. In the initial stretch on Vietnamese territory, it is also called Nam Te, flowing along the border and meeting the Tiểu Hắc tributary in Mu Ca, Muong Te. The Tiểu Hắc tributary enters Vietnam at Ka Lang, Muong Te, flowing along the border to the west and merging with the main stream of the Da River at Mu Ca.
The Da River has a large water discharge, supplying 31% of the water for the Red River and is a significant resource for hydroelectric power in Vietnam. In 1994, the Hoa Binh Hydropower Plant with a capacity of 1,920 MW and 8 turbines was inaugurated. In 2005, the Sơn La Hydropower Project began construction, designed with a capacity of 2,400 MW. The Lai Chau Hydropower Plant, with a capacity of 1,200 MW, is currently under construction, initiated in 2011 and expected to be completed by December 2016 upstream of this river. The basin has enormous potential resources with numerous rare minerals and characteristic ecosystems featuring high biodiversity.
3. Red River
The Red River has a very large average annual water discharge.
The Red River has a total length of 1,149 km, originating from China, flowing through Vietnam, and emptying into the South China Sea. The section flowing through Vietnam is 510 km long. This river is significant to the rice culture of Vietnam. The first contact point of the Red River with Vietnamese territory is at A Mu Sung commune (Bat Xat District, Lao Cai Province). In Lao Cai, the Red River is 73 meters above sea level. By the time it reaches Yen Bai, 145 km from Lao Cai, the river elevation drops to 55 meters. Between these two provinces, there are 26 rapids with swift currents. When reaching Viet Tri, the slope of the river decreases significantly, leading to a slower flow. The Red River Delta is located downstream of this river.
The Red River has a very large average annual water discharge, reaching 2,640 m³/s (at the river mouth) with a total volume of water flowing through to 83.5 billion m³; however, the water flow distribution is uneven. During the dry season, the flow reduces to about 700 m³/s, but during peak rainy seasons, it can reach up to 30,000 m³/s.
4. Ma River
The Ma River primarily flows through mountainous and midland regions.
The Ma River is a river of Vietnam and Laos, with a length of 512 km, of which the portion on Vietnamese territory is 410 km, and the portion in Laos is 102 km. The basin area of the Ma River is 28,400 km², with the part in Vietnam covering 17,600 km², an average elevation of 762 meters, an average slope of 17.6%, and a river density across the basin of 0.66 km/km². The average water discharge is 121 m³/s at Xa La and 341 m³/s at Cam Thuy. The Ma River flows mainly through mountainous and midland areas. The alluvium from the Ma River is a primary contributor to the Thanh Hoa plain, the third largest in Vietnam. The Ma River flows through a valley between the Su Xung Chao Chai and Pu Sam Sao mountain ranges, with most of its tributaries originating from these ranges.
The Ma River begins at the confluence of streams in the border region between Vietnam and Laos at Mường Lói in the southern part of Điện Biên (southern Điện Biên Province) at 21°0′49″N 103°7′38″E. The Pu Lau village, located north of Mường Lói, sits on a ridge that acts as a watershed divide between Nậm Nứa flowing northwest, part of the Mekong River system, and Nậm Ma flowing northeast, which is the source of the Ma River, locally known as Suối Sẻ. The river flows back into Vietnam at the Tén Tằn border gate in Mường Lát, Thanh Hóa. From here, it flows through Mường Lát and Quan Hóa, with a small section along Quan Hóa serving as the boundary between Thanh Hóa and Hòa Bình provinces. The total length of the Ma River system is 881 km, with a total basin area of 39,756 km², of which 17,520 km² is within Vietnam. The total average annual water volume of the entire river system is 19.52 billion m³.
5. Lam River (Ca River)
The Lam River is one of the two largest rivers in North Central Vietnam.
The Lam River (also known as Ngàn Cả, Ca River, Nậm Khan, Thanh Long River) is one of the two largest rivers in North Central Vietnam. The river originates from the Xiengkhuang Plateau in Laos. The portion flowing through Laos is called Nam Khan. The main section of the river flows through Nghe An, and the lower end of the Lam River merges with the La River from Ha Tinh, forming the boundary between Nghe An and Ha Tinh before emptying into the sea at Cửa Hội.
According to the Vietnam Encyclopedia, the total length of the river is approximately 512 km, with about 361 km flowing within Vietnamese territory. However, other sources suggest that this river has two main sources; if measured from the Nậm Mơn source (from the Pu Lôi range), the Lam River is 530 km long, while if measured from the Nậm Mô source (Trấn Ninh Plateau), the river’s length is 432 km. The basin area of this river is 27,200 km², of which 17,730 km² is in Vietnam.
On average, the Lam River is at an elevation of 294 meters with an average slope of 18.3%. The river density is 0.60 km/km². From the Vietnam-Laos border to Cửa Rào, the riverbed is steep with more than 100 rapids. From Cửa Rào downstream, smaller boats can navigate the river during the wet season. The total water volume is 21.90 km³, corresponding to an average annual flow of 688 m³/s and an annual runoff module of 25.3 l/s.km². The average flow per year at Cửa Rào is 236 m³/s, and at Dừa, it is 430 m³/s. The flood season lasts from June to November, coinciding with the rainy season, contributing about 74-80% of the total annual water volume.
6. Lo River
The section of the Lo River flowing in Vietnam is 274 km long.
The Lo River is a first-order tributary on the left bank of the Red River, flowing from China into the provinces of Ha Giang, Tuyen Quang, and Phu Tho in Vietnam. The segment of the Lo River that runs through Vietnam is 274 km long (different sources report lengths varying from 264 km to 277 km), making it one of the five longest rivers in Northern Vietnam (alongside the Red, Da, Lo, Cau, and Day rivers).
The 156 km stretch from the Viet Tri confluence to Tuyen Quang Port in Tuyen Quang Province accommodates vessels with a carrying capacity of 100 to 150 tons during both the dry and rainy seasons. From the city of Tuyen Quang to Ha Giang City, smaller vessels can engage in transportation during the rainy season.
7. Mekong River
The Mekong River originates from the Tibetan Plateau in China.
The Mekong River is one of the largest rivers in the world, originating from the Tibetan Plateau in Qinghai Province, China. It flows through China, Laos, Myanmar, Thailand, Cambodia, and discharges into the South China Sea in Vietnam. With a length of 4,350 km, it ranks 12th in the world and is the 10th largest river by water discharge. The average discharge is 13,200 m³/s, which can increase to 30,000 m³/s during flood season. Its basin covers an area of approximately 795,000 km² (according to the Mekong River Commission). This river starts from the high mountains of Qinghai Province, traverses Tibet, runs along the length of Yunnan Province (China), and passes through Myanmar, Thailand, Laos, and Cambodia before entering Vietnam.
Beginning in Phnom Penh, the Mekong divides into two branches: on the right is the Bassac River (known in Vietnam as Hau River) and on the left is the Mekong (known in Vietnam as Tien River), both flowing into the vast delta region of Southern Vietnam, with each river stretching approximately 220 – 250 km. In Vietnam, the Mekong is also referred to as the Great River or Mother River.
The International Nature Conservation Fund reports that scientists are searching for species such as the Australian catfish, giant stingrays, sharp-toothed fish, large carnivorous carps that can weigh over 90 kg and exceed 1.80 meters in length in the Mekong River. Additionally, the Mekong River is home to rare species of catfish and other unique fish, not to mention the giant Mekong catfish, making fishing tourism very popular in this area.
8. Chay River
The flow of the Chay River is quite complex, with a narrow, deep riverbed and steep banks featuring many rapids.
The Chay River is located in Northern Vietnam, originating from the southwest slope of Mount Tay Con Linh (2,419 m) and the northeast slope of Mount Kieu Lien Ti (2,402 m) in the upper reaches of the Chay River, in the northwest of Ha Giang Province. It flows through Lao Cai and Yen Bai provinces before merging into the Lo River at Doan Hung, Phu Tho Province, with a total length of 319 km.
The river’s flow is intricate, characterized by a narrow and deep riverbed, steep banks, and numerous rapids. In Ha Giang Province, the river flows east-west through Vi Xuyen, Hoang Su Phi, and Xin Man districts before traversing Si Ma Cai district in Lao Cai Province. Along this stretch, about 5 km of the Chay River serves as the Vietnam-China border between Lao Cai Province and Yunnan Province in China.
The Chay River is a stunning natural attraction for those who enjoy eco-tourism. During the dry season, the deepest parts of the river are only about 3 meters deep, allowing visitors to comfortably navigate upstream in metal boats. Scattered along the riverbanks are the simple homes of the Hmong, Dao, and Day ethnic groups. Occasionally, you may encounter bamboo rafts extracting sand, with the road to Bac Ha appearing as a white line winding along the mountainside in the distance.
