The Gulf of Tonkin is a gulf at the northwestern portion of the South China Sea, located off the coasts of Tonkin (northern Vietnam) and South China. It has a total surface area of . It is defined in the west and northwest by the northern coastline of Vietnam down to the Cồn Cỏ island,
Description and etymology
The name Tonkin, written "" in chữ Hán characters and in the Vietnamese alphabet, means "eastern capital", and is the former toponym for Hanoi, the present capital of Vietnam. It is not to be confused with Tokyo, which is also written "" and also means "eastern capital". During the French colonial era, the northern region of today's Vietnam was called Tonkin.
Bắc Bộ is the native Vietnamese name of Tonkin, which is the nowadays region of Northern Vietnam. The bay's Vietnamese and Chinese names – and , respectively – both mean "Northern Bay".
The Gulf of Tonkin is a relatively shallow portion of the Pacific Ocean; the majority of the gulf's ocean floor is less than in depth, and no part of the gulf is submerged in more than of water.
History
Gulf of Tonkin incident
On 4 August 1964, United States President Lyndon B. Johnson claimed that North Vietnamese forces had twice attacked American destroyers in the Gulf of Tonkin. Known today as the Gulf of Tonkin Incident, this event spawned the Gulf of Tonkin Resolution of 7 August 1964, ultimately leading to open war between North Vietnam and South Vietnam. It furthermore foreshadowed the major escalation of the Vietnam War in South Vietnam, which began with the landing of US regular combat troops at Da Nang in 1965.thumb|Map of the maritime border between Vietnam and China in the Gulf of Tonkin. The red dot is Bach Long Vi Island|left
Maritime border issue in the Gulf of Tonkin
On December 25, 2000, Vietnam and China signed an Agreement on the Delimitation of the Gulf of Tonkin. An Agreement took effect on June 30, 2004, officially defining the maritime border between the two countries in the Gulf of Tonkin.
thumb|The 2025 Vietnamese declaration on the baselines and width of territorial waters, which was made as a response to the parallel 2024 declaration from China. This map is wholly labeled in [[Vietnamese language and transcription.]]
On March 1, 2024, China issued a “Declaration on the baselines of the territorial waters in the northern part of the Gulf of Tonkin”. Vietnam calls on China to respect international law.
See also
- Port of Beibu Gulf
- Geography of China
- Geography of Vietnam
- Tonkin Gulf Yacht Club