Bản Giốc – Detian Falls or Bản Giốc Falls is a collective name for two waterfalls on the Quây Sơn River (Vietnamese: Sông Quây Sơn, chữ Nôm: 滝𢮿山; Chinese: 归春河, Pinyin: Guīchūn hé) that straddle the international border between China and Vietnam; more specifically located between the Karst hills of Daxin County, Guangxi and Trùng Khánh District, Cao Bằng Province.

A road running along the top of the falls leads to a stone marker that demarcates the border between China and Vietnam in French and Chinese.

Modern disputes arose as there are discrepancies as to the correlating legal documents on border demarcation and the placement of markers between the French and Qing administrations in the 19th century.

One faction holds that the entirety of these falls belongs to Vietnam, and that the stone tablet had been moved there some time during or after the brief Sino-Vietnamese war of 1979.

A road running along the top of the falls leads to a stone marker that demarcates the border between China and Vietnam in French and Chinese.

The disappearance or inaccurate replacement of markers and landmarks from time to time, and the varied patterns of transportation, settlement and land use from generation to generation, and the successive administrative differences throughout periods of war and strife led to both Vietnam and China understanding that exactly defining the border would increase prosperity in the long term.