Ban Gioc – Detian Falls or Ban Gioc falls is a collective name for two waterfalls on the Quây Sơn River, 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. The waterfall is 272 km (169 mi) north of Hanoi.
Over thousands of years the waterfall has eroded its crest and slowly moved upstream. It currently appears to be two waterfalls most of the time but when the river is swollen due to summer rains can form one fall again. The waterfall drops 30 m (98 ft). It is separated into three falls by rocks and trees, and the thundering effect of the water hitting the cliffs can be heard from afar.